• The Korean Journal of Physiology and Pharmacology
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• 제6권2호
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• pp.109-112
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• 2002

The signal pathways involved in the regulation of AP-1 DNA binding activity in long-term nicotine stimulated bovine adrenal medullary chromaffin (BAMC) cells have not been well characterized. To understand the involvement of second messengers in the regulation of AP-1 DNA binding activity, the present study was designed to define the time-course for inhibition of nicotine-induced responses by cholinergic antagonists, $Ca^{2+}$ and calmodulin (CaM) antagonists, and calcium/calmodulin-dependent protein kinase (CaMK) II inhibitor using electrophoretic mobility shift assay. Nicotine $(10{\mu}M)$ stimulation increased AP-1 DNA binding activity at 24 hr after treatment. Posttreatment with hexamethonium (1 mM) plus atropine $(1{\mu}M)$ (HA), nimodipine $(1{\mu}M),$ or calmidazolium $(1{\mu}M)$ at 0.5, 3, and 6 hr after the nicotine treatment significantly inhibited the AP-1 DNA binding activity increased by long-term nicotine stimulation. However, posttreatment with HA, nimodipine, or calmidazolium at 9 or 12 hr after the nicotine treatment did not affect the nicotine-induced increase of AP-1 DNA binding activity. The pretreatment of BAMC cells with various concentrations of KN-62 inhibited the increase of AP-1 DNA binding activity induced by nicotine in a concentration-dependent manner. KN-62 $(10{\mu}M)$ posttreatment beginning at 0.5, 3, or 6 hr after the nicotine treatment significantly inhibited the increase of AP-1 DNA binding activity. However, KN-62 posttreatment beginning at 9 or 12 hr after the nicotine treatment did not affect the increase of AP-1 DNA binding activity. This study suggested that stimulation (for at least 6 hr) of nicotinic receptors on BAMC cells was necessary for increase of AP-1 DNA binding activity, and activation of $Ca^{2+},$ CaM, and CaMK II up to 6 hr at least seemed to be required for the increase of nicotine-induced AP-1 DNA binding activity.

• BMB Reports
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• 제38권4호
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• pp.474-480
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• 2005

Curcumin, a major active component of turmeric, has been identified as an inhibitor of the transcriptional activity of activator protein-1 (AP-1). Recently, it was also found that curcumin and synthetic curcumin derivatives can inhibit the binding of Jun-Fos, which are the members of the AP-1 family, to DNA. However, the mechanism of this inhibition by curcumin and its derivatives was not disclosed. Since the binding of Jun-Fos dimer to DNA can be modulated by redox control involving conserved cysteine residues, we studied whether curcumin and its derivatives inhibit Jun-Fos DNA binding activity via these residues. However, the inhibitory mechanism of curcumin and its derivatives, unlike that of other Jun-Fos inhibitors, was found to be independent of these conserved cysteine residues. In addition, we investigated whether curcumin derivatives can inhibit AP-1 transcriptional activity in vivo using a luciferase assay. We found that, among the curcumin derivatives examined, only inhibitors shown to inhibit the binding of Jun-Fos to DNA by Electrophoretic Mobility Shift Assay (EMSA) inhibited AP-1 transcriptional activity in vivo. Moreover, RT-PCR revealed that curcumin derivatives, like curcumin, downregulated c-jun mRNA in JB6 cells. These results suggest that the suppression of the formation of DNA-Jun-Fos complex is the main cause of reduced AP-1 transcriptional activity by curcuminoids, and that EMSA is a suitable tool for identifying inhibitors of transcriptional activation.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.925-928
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• 1999

The process of transcription is the major point at which gene expression is regulated. The jun and fos families of eukaryotic transcription factor heterodimerize to form complexes capable of binding 5'-TGAGTCA-3'DNA elements (AP-1 binding site). To search for the inhibitors of the jun-fos-DNA complex formation, several natural products extracts were screened and methanol extract of tanshen (the dried roots of Salvia miltiorrhiza Bunge) showed remarkable inhibitory activity. The active compounds of the extracts were purified using re-peated column chromatography and recrystallization. Their structures were identified as tanshinone I and tanshinone IIA. Through the electrophoresis mobility shift assay and cell cytotoxicity test, tanshinone I and tanshinone IIA were identified as inhibitors that suppress not only AP-1 function but also the cell proliferation. Tanshinone I also suppressed the jun-fos-DNA complex formation in TPA-induced NIH 3T3 cells.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.180-180
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• 1996

Previous studies have shown that kainic acid (KA) causes an elevation of hippocampal proenkephalin mRNA level. However, the role of proto-oncogene products, such as c-Fos, c-Jun and Fra proteins in the regulation of KA-induced proenkephalin mRNA increase in the hippocampus has not been well characterized. Thus, in the present study, the effect of cycloheximide (CHX) on KA-induced proenkephalin mRNA and immediate early gene products induction was examined. After pretreating with either vehicle or CHX (20 mg/kg, s.c.) for 30 min, KA (10 mg/kg) was administered s.c. The animals were sacrificed 1,2, or 8 hrs after KA administration. Total RNA and were isolated for Northern blot assay, and proteins were isolated for Western and electrophoretic gel-shift assays. First, we found that CHX inhibited KA-induced proenkephalin mRNA increase without altering intracellular proenkephalin protein level. Secondly, Western blot assays showed that KA increased c-Fos, c-Jun and Fra proteins at 1,2, and 8 hrs and CHX inhibited these immediate early gene products. Finally, electrophoretic gel shift assays revealed that KA increased both AP-1 and ENKCRE-2 DNA binding activities. Furthermore, CHX attenuated KA-induced AP-1 and ENKCRE-2 DNA binding activities. Both AP-1 and ENKCRE-2 DNA binding activities were abolished by cold AP-1 or ENKCRE-2 oligonucleotides, and further reduced by antibodies against c-Fos or c-Jun. Antibody against CREB reduced ENKCRE-2, but not AP-1, DNA binding activity. Our results suggest that on-going protein synthesis is required for elevation of hippocampal proenkephalin mRNA level induced by KA. All c-Fos, c-Jun, and Fra proteins appears to be involved in the regulation of hippocampal proenkephalin mRNA level induced by KA (This study was supported by a grant from KOSEF).

• 대한한의학회지
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• 제23권1호
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• pp.50-60
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• 2002

Objectives: Sunghyangjunggisan (SHJS) is a commonly prescribed drug with a wide neuropharmacological spectrum. The water extracts of SHJS were found to be protective against neurotoxicity elicited by deprivation of serum and glucose. Methods: The morphological examination and Hoechst staining of nucleus also clearly showed that the extracts attenuated the cell shrinkage, membrane blebbing, representing typical neuronal apoptotic phenomena and nucleosome-sized fragmentation under the microscope in PC 12 rat pheochromocytoma cells. Results: Activation of protein kinase A (PKA) with dibutyl-cAMP and forskolin also protected during glucose deprivation, although it was not additive with the effect provided by phorbol ester. Interestingly, treatment with the protein kinase A inhibitor, KT5720, was not neuroprotective in the presence of SHJS. Electrophoretic mobility shift assays were used to characterize the neuroprotective binding of nuclear proteins to consensus sequences for AP-l, nuclear factor kappa B ($NF-{\kappa}B$) after glucose deprivation. When PC 12 cells are induced to undergo apoptosis by serum deprivation, AP-l and $NF-{\kappa}B$ DNA binding activity transiently increases to a slight degree. This stimulation is blocked by the water extracts of SHJS. The site of action of the drugs appeared to involve specific inhibition of AP-1 and nuclear factor kB binding activity. Conclusions: Taken together, these results suggested the possibility that the extracts of SHJS might provide a neurotrophic-like activity in PC 12 cells.

• BMB Reports
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• 제34권1호
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• pp.28-32
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• 2001

The Fos-Jun heterodimers are part of the regulatory network of gene expression and nuclear proteins encoded by proto-oncogenes. The activation of Fos-Jun is important in the transmission of the tumor-promoting signal from the extracellular environment to the nuclear transcription mechanism. To search for the inhibitors of the Fos-Jun DNA complex formation, several natural products were screened and water-soluble paeoniflorin reduced the binding activity of the Fos-Jun heterodimer. This active compound was purified by silica gel column chromatography and HPLC. The electrophoresis mobility shift assay and reverse-phase HPLC test showed that paeoniflorin reduced the AP-l function. The cytotoxic effect of paeoniflorin was observed in HL-60. These results indicate that paeoniflorin blocks the Fos-Jun heterodimer-binding site of the AP-l DNA and it also has cytotoxic effects on human leukemia cell lines.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 제3회 추계심포지움
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• pp.17-21
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• 1995

대부분의 인슐린의 작용들은 인슐린 수용체를 통하여 이루어진다. 인슐린이 수용체에 결합하면, 수용체 고유의 tyrosine kinase 효소활성의 증가를 유발시키며, 결과적으로 세포내에 존재하는 기질 단백질, IRS-1, 의 tyrosine 잔기의 인산화를 증가시키게 된다. 이후, 여러 형태의 serine / threonine protein kinase 의 연속적인 활성화가 일어난다. 이들에 부가해서, 인슐린의 효자는 세포핵 내에까지 전달되어 유전자 발현의 조절과 같은 세포핵 고유의 활동에도 관여한다. 현재, 세포막에서 시작된 인슐린의 신호들이 세포핵까지 전달되는 정확한 기전에 대해서는 알려진 바 없지만, 최근의 연구에 의하면 MAP Kinase 와 S6 Kinase 그리고 Transcription Factor AP-1의 중요성이 제시되고 있다. 특히 유전자 조절 기전에는 핵단백질인 transcription factor의 인산화 반응이 큰 역할을 한다고 보고되고 있는바, 본 연구에서 AP-1. transcription factor 의 인산화 반응이 인슐린의 신호전달계에 미치는 역할에 대하여 고찰하였다. 요약하면, AP-1 transcription factor의 구성원인 c-Jun, c-Fos 그리고 Fos 관련 단백질들의 인산화가 인슐린에 의해 증가되며, 동시에 그들의. DNA-binding activity 와 유전자 발현의 활성이 증가됨을 밝힘으로써, AP-1 transcription factor의 인산화 반응이 인슐린의 핵 내에서의 작용기전에 중요한 역할을 함이 제시되고 있다. 또한 AP-1 의 인산화 반응에 관여하는 세포핵 protein kinase로서 Casein Kinase II 의 중요성이 밝혀졌다.

• International Journal of Oral Biology
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• 제42권3호
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• pp.117-121
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• 2017

We have previously shown that the specific phosphatidylinositol 3-kinase inhibitor LY294002 (LY29), and its inactive analog LY303511 (LY30), inhibit a monocyte chemoattractant protein-1 (MCP-1) expression in human umbilical vein endothelial cells; these results suggest the potential of LY30 as an anti-inflammatory drug. In this study, we determined the effects of LY30 on the production of various inflammatory cytokines in human macrophagic THP-1 cells which were stimulated with lipopolysaccharide (LPS). LY30 selectively suppressed the mRNA expression of IL-12 p40, $TNF-{\alpha}$, and MCP-1 without affecting the expression of $IL-1{\alpha}$, IL-6, and IL-8. Inhibition of the production of IL-12 and $TNF-{\alpha}$ by LY30 was also demonstrated using ELISA assays. In order to elucidate the mechanisms of the action of LY30, we examined the role played by the mitogen-activated protein kinases and the key transcription factors, AP-1 and $NF-{\kappa}B$ in LPS-stimulated THP-1 cells. The results revealed that LY30 inhibited LPS-induced activation of ERK, but not p38 or JNK. Furthermore, the AP-1 DNA binding activity was suppressed by LY30 based upon the dosage, whereas $NF-{\kappa}B$ DNA binding was not affected. These results suggest that LY30 selectively inhibits cytokine production in the LPS-stimulated macrophagic THP-1 cells by down-regulating the activation of ERK and AP-1.

• 대한본초학회지
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• 제22권3호
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• pp.67-76
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• 2007

Objectives : This study was carried out to know the effect of Cordyceps sinensis(CS) on the immune inflammatory responses of athritis and function. Methodes : To analyse immunomodulatory effects of CS, cytotoxicity and inhibition of proliferation against of synovial cells, gene expression of inflammatory mediators such as TNF-$\alpha$, IL-1$\beta$ and IL-6, DNA-binding activity of $NF-_{k}B$ and AP-1 were measured in vitro. Results : CS didn't show cytotoxicity against human synovial cells and inhibited proliferation of human synovial cells in a dose-dependent manner in combination with rIL-6. CS reduced the gene expression of IL-6 and IL-1$\beta$ in a dose- dependent manner but didn't reduced that of TNF-$\alpha$ in human synovial cells. CS reduced the binding-activity of $NF-_{k}B$ and also reduced that of AP-1 remarkably. Conclusion: We found out that Cordyceps sinensis has immunomodulatory effect of suppressing synovial cells. And Cordyceps sinensis will be used as a stable remedium in the auto-immune disease in the future.

• 대한본초학회지
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• 제28권1호
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• pp.33-42
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• 2013

Objective : Morus alba Linne Root Bark (MRAL) is a medicinal herb in Korean Medicine, known for its anti-inflammatory and anti-allergic properties. However, its mechanisms of action and the cellular targets have not yet been found and the study was developed to investigate the allergic suppressive effect of MRAL. The purpose of this study is to investigate the allergic suppressive effects of MRAL on activation of MC/9 mast cells. Methods : Cytotoxic activity of MRAL (50, 100, 200, 400 ${\mu}g/mL$) on MC/9 mast cells measured using EZ-Cytox cell viability assay kit (WST reagent). The levels of interleukin-5 (IL-5), IL-13 and IL-4, IL-5, IL-6, IL-13 mRNA expression were measured by enzyme-linked immunosorbent assay (ELISA) and real-time PCR respectively. The expression of transcription factors such as GATA-1, GATA-2, NFAT, AP-1 and NF-${\kappa}B$ p65 DNA binding activity were measured by western blot and electrophoresis mobility shift assay (EMSA). Results : Our results indicated that MRAL (50 ${\mu}g/mL$, 100 ${\mu}g/mL$) significantly inhibited PMA/Ionomycin-induced production of IL-5 and IL-13 and the expression of IL-4, IL-5, IL-6 and IL-13 mRNA in MC/9 mast cells. Moreover, MRAL (50 ${\mu}g/mL$, 100 ${\mu}g/mL$) inhibited PMA/Ionomycin-induced GATA-1, GATA-2, NFAT-1, NFAT-2, c-Fos protein expression and NF-${\kappa}B$ p65 DNA binding activity in MC/9 mast cells. Conclusions : In conclusion, we suspect the anti-allergenic activities of MRAL, may be related to the regulation of transcription factors GATA-1, GATA-2, NFAT-1, NFAT-2, c-Fos and NF-${\kappa}B$ p65 DNA binding assay causing inhibition of Th2 cytokines IL-5 and IL-13 in mast cells.