• 제목/요약/키워드: Ligand effect

검색결과 423건 처리시간 0.028초

ARYL HYDROCARBON- AND ESTROGEN-MEDIATED SIGNALS POSSIBLY CROSS TALK TO REGULATE CYP1A1 GENE EXPRESSION

  • Joung, Ki-Eun;Kim, Yeo-Woon;Min, Kyung-Nan;Sheen, Yhun-Yhong
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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    • pp.112-112
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    • 2001
  • 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxin that activates the aryl hydrocarbon receptor (AhR) and disrupts multiple endocrine signaling pathways by enhancing ligand metabolism, altering hormone synthesis, down regulating receptor levels, and interfering with gene transcription. And TCDD-mediated gene transactivation via the AhR has been shown to be dependent upon estrogen receptor (ER) expression in human breast cancer cells. In the present study, we have examined the effect of natural estrogen, phytoestrognes and environmental estrogens on the regulation of CYP1A1 gene expression in MCF-7 human breast cancer cell line. that ER and AhR are co-expressed. pCYP1A1 -luc reporter gene was transiently transfected into MCF-7 cells. These cells were treated with various chemicals and then luciferase assay was carried out. 17be1a-estradiol significantly inhibited TCDD stimulated luciferase activity dose dependently and this inhibition was partially recovered by concomitant treatment of tamoxifen. 17beta-estradiol metabolites, 2-hydroxyestradiol and 16alpha-estriol resulted in less potent inhibitory effect than estradiol and synthetic estrogen, diethylstilbestrol (DES) showed no effect on CYP1A1 gene expression. This study demonstrated that estrogen down-regulated TCDD stimulated CYP1A1 expression via ER mediation. And we have found out that several flavonoids such as genistein, kaempferol, daidzein, naringenin, and alkylphenols such as nonylphenol, 4-octylphenol and resveratrol also inhibited TCDD induced CYP1A1 expression like estrogen.

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The Effect of Toll-like Receptor 2 Activation on the Non-opsonic Phagocytosis of Oral Bacteria and Concomitant Production of Reactive Oxygen Species by Human Neutrophils

  • Kim, Kap Youl;Choi, Youngnim
    • International Journal of Oral Biology
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    • 제41권1호
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    • pp.17-23
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    • 2016
  • Chronic/cyclic neutropenia, leukocyte adhesion deficiency syndrome, Papillon-$Lef{\grave{e}}vre$ syndrome, and $Ch{\grave{e}}diak$-Higashi syndrome are associated with severe periodontitis, suggesting the importance of neutrophils in the maintenance of periodontal health. Various Toll-like receptor (TLR) ligands are known to stimulate neutrophil function, including FcR-mediated phagocytosis. In the present study, the effect of TLR2 activation on the non-opsonic phagocytosis of oral bacteria and concomitant production of reactive oxygen species (ROS) by human neutrophils was evaluated. Neutrophils isolated from peripheral blood were incubated with Streptococcus sanguinis or Porphyromonas gingivalis in the presence of various concentrations of $Pam_3CSK_4$, a synthetic TLR2 ligand, and analyzed for phagocytosis and ROS production by flow cytometry and chemiluminescence, respectively. $Pam_3CSK_4$ significantly increased the phagocytosis of both bacterial species in a dose-dependent manner. However, the enhancing effect was greater for S. sanguinis than for P. gingivalis. $Pam_3CSK_4$ alone induced ROS production in neutrophils and also increased concomitant ROS production induced by bacteria. Interestingly, incubation with P. gingivalis and $Pam_3CSK_4$ decreased the amounts of ROS, as compared to $Pam_3CSK_4$ alone, indicating the possibility that P. gingivalis survives within neutrophils. However, neutrophils efficiently killed phagocytosed bacteria of both species despite the absence of $Pam_3CSK_4$. Although P. gingivalis is poorly phagocytosed even by the TLR2-activated neutrophils, TLR2 activation of neutrophils may help to reduce the colonization of P. gingivalis by efficiently eliminating S. sanguinis, an early colonizer, in subgingival biofilm.

Lanthanides-Benzoylformate 착물 형성에 관한 열역학적 연구 (Thermodynamic Properties of Lanthanides Complexes with Benzoylformate Anion)

  • 김영인;박선금
    • 대한화학회지
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    • 제37권4호
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    • pp.442-447
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    • 1993
  • 수용액 내에서 란탄(Ⅲ)-benzoylformate 착물 형성 반응의 열역학적 파라메타들(${\Delta}$G, ${\Delta}$H 및 ${\Delta}$S)을 pH 및 엔탈피 적정 방법을 사용하여 이온세기 $0.1M NaClO_4$, 25$^{\circ}C$ 조건하에서 구하였다. 란탄-benzoylformate 착물의 안정도 상수(1:1) 값으로부터 benzoylformate가 두자리 리간드로 작용함을 알 수 있었다. 열역학적 실험 결과는 카르복실기와 함께 케톤기 산소원자가 결합에 참여하여 킬레이트를형성하는 것으로 판단되었으며, 이는 benzoylformate 리간드 내에 존재하는 벤젠고리의 공액 효과에 의해 케톤기의 산소원자의 전하량이 증가된 결과로 해석되었다. 착물의 안정도는 엔트로피 효과 뿐 아니라, 금속-산소결합 형성에 따른 엔탈피 효과에도 기인하였다.

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Substituent Effect on the Structure and Biological Property of 99mTc-Labeled Diphosphonates: Theoretical Studies

  • Qiu, Ling;Lin, Jian-Guo;Gong, Xue-Dong;Cheng, Wen;Luo, Shi-Neng
    • Bulletin of the Korean Chemical Society
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    • 제33권12호
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    • pp.4084-4092
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    • 2012
  • Theoretical calculations based on density functional theory (DFT) were performed to study the substituent effect on the geometric and electronic structures as well as the biological behavior of technetium-99m-labeled diphosphonate complexes. Optimized structures of these complexes are surrounded by six ligands in an octahedral environment with three unpaired 4d electrons ($d^3$ state) and the optimized geometry of $^{99m}Tc$-MDP agrees with experimental data. With the increase of electron-donating substituent or tether between phosphate groups, the energy gap between frontier orbitals increases and the probability of non-radiative deactivation via d-d electron transfer decreases. The charge distribution reflects a significant ligand-to-metal electron donation. Based on the calculated geometric and electronic structures and biologic properties of $^{99m}Tc$-diphosphonate complexes, several structure-activity relationships (SARs) were established. These results may be instructive for the design and synthesis of novel $^{99m}Tc$-diphosphonate bone imaging agent and other $^{99m}Tc$-based radiopharmaceuticals.

파골세포의 골 흡수에 미치는 녹용의 억제효과 (Inhibitory Effect of Deer Antler on Osteoclastic Bone Resorption)

  • 김윤경;최윤홍;송정훈;장성조;김현정;이창훈;안선호;이지은;김정중;최민규
    • 동의생리병리학회지
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    • 제23권6호
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    • pp.1299-1304
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    • 2009
  • We have previously shown that water extract of deer antler (WEDA) inhibited RANKL-mediated osteoclast differentiation from bone marrow macrophages by suppressing c-Fos and NFATc1 expression. Thus, we examined the effect of WEDA in inflammation-induced bone loss in vivo. Here we found that WEDA inhibited osteoblast-supported osteoclast differentiation induced by lipopolysaccharide (LPS). However, WEDA did not suppress the expression of receptor activator of NF-${\kappa}B$ ligand (RANKL) in response to LPS in osteoblasts. WEDA also inhibited the bone resorptive activity of mature osteoclasts. To examine the effect of WEDA on bone loss, when LPS injected subcutaneously in mice, bone loss was greatly increased, but WEDA treatment inhibited LPS-mediated bone loss. Taken together, we conclude that WEDA inhibited osteoclast differentiation and bone resorption in vitro and in vivo. Thus WEDA may be useful in the treatment of bone-related disorders.

Lactobacillus fermentum으로 발효한 쌍화탕의 파골 세포 분화와 난소 적출한 랫트의 골다공증에 미치는 영향 (Effect of Ssangwha-tang Fermented by Lactobacillus fermentum on Osteoclast Differentiation and Osteoporosis of Ovariectomized Rats)

  • 심기석;이지혜;이재훈;마진열
    • 한국한의학연구원논문집
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    • 제16권1호
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    • pp.149-155
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    • 2010
  • Objective : Ssangwha-tang is a traditional medicine formula widely prescribed for a decrease of fatigue after an illness in Korea. The aim of this study is to investigate the effect of Ssangwha-tang fermented by Lactobacillus fermentum (SF) on osteoclast differentiation in vitro and on bone metabolism of an ovariectomized rat in vivo. Methods : Tartrate-resistant acid phosphatase activity and staining were applied to evaluate the formation of osteoclasts. Ovariectomized rats were orally administrated with SF (30 ml/kg/day) for 12 weeks. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglyceride, phosphate, calcium levels were determined. Effect of SF on bone loss were studied by histological analysis and the measurement of bone mineral density. Results : SF significantly inhibited tartrate-resistant acid phosphatase activity and formation of osteoclasts in RAW264.7 cells stimulated by receptor activator for nuclear factor ${\kappa}B$ (NF-${\kappa}B$) ligand (RANKL). In addition, SF significantly decreased the level of triglyceride and increased the level of low-density lipoprotein. Moreover, the decrease of trabeculae of the femur was partially prevented in ovariectomized rats administrated with SF. Conclusions : SF treatment could prevent ovariectomy induced bone loss and its effects could be medicated by the inhibition of osteoclastogenesis.

Tomplasma gondii의 숙주세포 침투를 억제하는 우태아혈청 성분 (Inhibition of entry of Toxoplasma gonldii into MDCK cells by fetal bovine serum)

  • 남호우;김동진
    • Parasites, Hosts and Diseases
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    • 제31권4호
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    • pp.379-381
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    • 1993
  • 우태아혈청의 성분이 Toxoplasma의 숙주세포 침투를 억제하는 현상을 보여 이를 보고하고자 한다. MDCK세포를 숙주로 하여 Toxoplasma의 RH주를 첨가하였을 때, 우태아혈청 농도 1%(v/v) 에서 억제 효과가 나타나기 시작하여 5%일때 침투능을 반감시켰다. 우태아절청의 비동화 여부는 억제 효과에 영향을 미치지 못하였으며, 우태아혈청을 $95^{\circ}C$에서 10분간 처리하여 억제물질의 기능을 파괴시킬 때 억제 효과는 약간 감소되었다. Toxoprasma를 먼저 우태아혈청으로 처리한 후 숙주 세포에 첨가하였을 때 침투능에는 효과를 미치지 못하였으나, Tomplasma를 숙주세포와 배양하면서 우태아혈청을 첨가하였을 때에는 시간의 경과에 따라 침투능을 억제시켰다. 이상의 결과로 우태아혈청에 Toxoplasma의 숙주세포 침투를 억제하는 성분이 존재하는 것을 확인하였으며, 억제 방법이 침투하는 순간에 일어나며, 억제물질의 기능을 통해서라기 보다는 구조를 통해서 이루어진다고 추정할 수 있었다.

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부자와 육계 병용투여 시 파골세포 분화 억제에 미치는 영향 (Effect of Co-administration of Aconiti Lateralis Preparata Radix and Cinnamomi Cortex on Osteoclast Differentiation)

  • 정기은;김정영;김지훈;한상용;김윤경
    • 대한본초학회지
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    • 제29권2호
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    • pp.61-67
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    • 2014
  • Objectives : Aconiti Lateralis Preparata Radix (Aconitum Carmichaeli, AC) and Cinnamomi Cortex (Cinnamomi Cortex, CC) have been treated to elderly for kidney yang enhancement in Korean traditional medicine. In this study, the effects of water extract of AC and CC on RANKL (Receptor Activator for Nuclear Factor ${\kappa}B$ Ligand)-induced osteoclast differentiation were evaluated in culture system. Methods : MTT assay was used to evaluate the potential cytotoxicity of AC and CC extracts in bone macrophage marrows (BMMs) stimulated with M-CSF. TRAP (tartrate-resistant acid phosphatase) staining and TRAP activity were performed to know the inhibitory effect on osteoclast differentiation. The protein expression levels of nuclear factors such as activated T cell(NFAT)c1, c-Fos, MAPKs and ${\beta}$-actin in cell lysates treated with AC and CC extracts were analysed by western blotting. Results : AC, CC extracts and their co-administration inhibited significantly RANKL-induced osteoclast differentiation in BMMs in a dose dependent manner without toxicity. Each AC and CC extracts inhibited the phosphorylation of p38. Also, AC and CC extracts, respectively, inhibited the protein expression of c-Fos and NFATc1 more than Co-administration of AC and CC even if all treatments did. It was observed that RANKL-induced degradation of I-${\kappa}B$ is significantly suppressed by all treatments. Conclusions : Taken together, It was concluded that AC and CC have beneficial effect on osteoporosis by inhibition of osteoclast differentiation. Thus, Atractylodis AC and CC could be a treatment option for osteoporosis.

부자 추출물이 LPS로 유도된 C57BL6 마우스의 패혈증 연관 급성 폐 손상에 미치는 영향 (Effect of Water Extract of Aconiti Lateralis Preparata Radix on Lung Injury in LPS-induced Septic C57BL6 Mice)

  • 이인승;부민아;심재욱;백승호;박진봉
    • 대한융합한의학회지
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    • 제4권1호
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    • pp.19-27
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    • 2022
  • Objectives: TSepsis and subsequent acute lung injury (ALI) is a critical state of health caused by infection or endotoxins. This study was conducted to evaluate the effect of Water Extract of Aconiti Lateralis Preparata Radix (AR) on lipopolysaccharide (LPS)-induced sepsis in C57BL/6 mice. Methods: Male C57BL/6 mice were intraperitoneally injected with LPS to induce sepsis and ALI. AR was orally fed twice at 30 min and 180 min after LPS injection. At 24 h post injection, mice were sacrificed, bronchoalveolar lavage fluid (BALF) and blood was collected, and lung tissue was harvested. Hematoxylin and eosin staining was performed in lung tissues, wet/dry ratio of the lung tissue was measured, and the serum cytokine and chemokine levels were analyzed. Results: AR revoked the LPS-induced pathological changes in lung tissues, such as abnormal histological structures, immune cell infiltration and lung edema. Also, AR suppressed the neutrophil infiltration into the lung which was greatly increased by LPS injection based on the cell content of collected BALF. Serum cytokines and chemokines were measured, and AR reversed the LPS-induced increase of cytokines such as interleukin 1 beta, interleukin 6, tumor necrosis factor alpha and chemokines including C-X-C motif chemokine ligand 1 and 2. Conclusion: TAR showed a protective effect in the pathological progress of LPS-induced ALI. Especially, AR suppressed lung edema and infiltration of neutrophils by inhibiting cytokine and chemokine expressions. Such results demonstrate the potential of AR as a therapeutic agent for sepsis and sepsis-induced ALI.

Parthenolide inhibits osteoclast differentiation and bone resorbing activity by down-regulation of NFATc1 induction and c-Fos stability, during RANKL-mediated osteoclastogenesis

  • Kim, Ju-Young;Cheon, Yoon-Hee;Yoon, Kwon-Ha;Lee, Myeung Su;Oh, Jaemin
    • BMB Reports
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    • 제47권8호
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    • pp.451-456
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    • 2014
  • Parthenolide, a natural product derived from Feverfew, prevents septic shock and inflammation. We aimed to identify the effects of parthenolide on the RANKL (receptor activator of $NF-{\kappa}B$ ligand)-induced differentiation and bone resorbing activity of osteoclasts. In this study, parthenolide dose-dependently inhibited RANKL-mediated osteoclast differentiation in BMMs, without any evidence of cytotoxicity and the phosphorylation of p38, ERK, and $I{\kappa}B$, as well as $I{\kappa}B$ degradation by RANKL treatment. Parthenolide suppressed the expression of NFATc1, OSCAR, TRAP, DC-STAMP, and cathepsin K in RANKL-treated BMMs. Furthermore, parthenolide down-regulated the stability of c-Fos protein, but could not suppress the expression of c-Fos. Overexpression of NFATc1 and c-Fos in BMMs reversed the inhibitory effect of parthenolide on RANKL-mediated osteoclast differentiation. Parthenolide also inhibited the bone resorbing activity of mature osteoclasts. Parthenolide inhibits the differentiation and bone-resolving activity of osteoclast by RANKL, suggesting its potential therapeutic value for bone destructive disorders associated with osteoclast-mediated bone resorption.