• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.101-101
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• 2003

Prostaglandins (PGs) and nitric oxide (NO) produced by inducible cyclooygenase (COX-2) and nitric oxide synthase (iNOS), respectively, have been implicated as important mediators in the process of inflammation and carcinogenesis. On this line, the potential COX-2 or iNOS inhibitors have been considered as anti-inflammatory and cancer chemopreventive agents. In our continuing efforts of searching for novel cancer chemopreventive agents from natural products, we isolated natural sesquiterpenoids as potential COX-2 and iNOS inhibitors in cultured lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells. Alantolactone, a natural eudesmane-type sesquiterpenoid, exhibited a potent inhibition of COX-2 (IC50 = 0.4 $\mu\textrm{g}$/$m\ell$) and iNOS activity (IC50 = 0.08 $\mu\textrm{g}$/$m\ell$) in the assay system determined by PGE2 and NO accumulation, respectively. The inhibitory potential of alantolactone on the PGE2 and NO production was well coincided with the suppression of COX-2 and iNOS protein and mRNA expression in LPS-induced macrophages. Furthermore, alantolactone inhibited NF-kB but not AP-l binding activity on nuclear extracts evoked by LPS-stimulated macrophage cells, suggesting the possible involvement of NF-kB in the regulation of COX-2 and iNOS expression. In further study with COX-2-expressing human colon HT-29 cells, alantolactone inhibited the cell proliferation, down-regulated COX-2, and inhibited the ERK phosphorylation in the early time. These results suggest that a natural sesquiterpenoid alantolactone might be a potential lead candidate for further developing COX-2 or iNOS inhibitor possessing cancer chemopreventive or anti-inflammatory activity

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1207-1213
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• 2006

Tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$ has been implicated in skeletal diseases by promoting bone loss in inflammatory bone diseases. In the present study, we examined the effects of $TNF-{\alpha}$ on osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). $TNF-{\alpha}$ dose-dependently promoted matrix mineralization of hBMSCs with a maximal stimulation at 2ng/ml. $TNF-{\alpha}$ increased expression of alkaline phosphatase, which plays a crucial role for the matrix deposition. The $TNF-{\alpha}-stimulated$ osteoblastic differentiation was not affected by $NF_kB$ inhibitors, BAY and SN50. However, a JNK-specific inhibitor, SP600125 completely abolished the $TNF-{\alpha}-stimulated$ matrix mineralization and expression of alkaline phosphatase. These results suggest that $TNF-{\alpha}$ enhances osteoblastic differentiation of hBMSCs through JNK-dependent pathway.

• BMB Reports
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• v.54 no.9
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• pp.458-463
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• 2021

Cytokines activate inflammatory signals and are major mediators in progressive β-cell damage, which leads to type 1 diabetes mellitus. We recently showed that the cell-permeable Tat-CIAPIN1 fusion protein inhibits neuronal cell death induced by oxidative stress. However, how the Tat-CIAPIN1 protein affects cytokine-induced β-cell damage has not been investigated yet. Thus, we assessed whether the Tat-CIAPIN1 protein can protect RINm5F β-cells against cytokine-induced cytotoxicity. In cytokine-exposed RINm5F β-cells, the transduced Tat-CIAPIN1 protein elevated cell survivals and reduced reactive oxygen species (ROS) and DNA fragmentation levels. The Tat-CIAPIN1 protein reduced mitogen-activated protein kinases (MAPKs) and NF-κB activation levels and elevated Bcl-2 protein, whereas Bax and cleaved Caspase-3 proteins were decreased by this fusion protein. Thus, the protection of RINm5F β-cells by the Tat-CIAPIN1 protein against cytokine-induced cytotoxicity can suggest that the Tat-CIAPIN1 protein might be used as a therapeutic inhibitor against RINm5F β-cell damage.

• Molecules and Cells
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• v.26 no.4
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• pp.396-403
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• 2008

The first ORF of the ARV S1133 S1 segment encodes the nonstructural protein p10, which is responsible for the induction of cell syncytium formation. However, p10-dependent signaling during syncytium formation is fully unknown. Here, we show that dominant negative RhoA, Rho inhibitor C3 exoenzyme, ROCK/Rho-kinase inhibitor Y-27632 and Rac1 inhibitor NSC23766 inhibit p10-mediated cell fusion. p10 over-expression is concomitant with activation and membrane translocation of RhoA and Rac1, but not cdc42. RhoA and Rac1 downstream events, including JNK phosphorylation and transcription factor AP-1 and $NF-{\kappa}B$ activation, as well as MLC expression and phosphorylation are simultaneously activated by p10. p10 point mutant T13M possessed 20% fusion-inducing ability and four p10 fusion-deficient mutants V15M, V19M, C21S and L32A reduced or lost their ability to activate RhoA and Rac1 signaling. We conclude that p10-mediated syncytium formation proceeds by utilizing RhoA and Rac1-dependent signaling.

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.30-41
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• 2024

The dense granule protein of Toxoplasma gondii, inhibitor of signal transducer and activator of transcription 1 (IST) is an inhibitor of signal transducer and activator of transcription 1 (STAT1) transcriptional activity that binds to STAT1 and regulates the expression of inflammatory molecules in host cells. A sterile inflammatory liver injury in pathological acute liver failures occurs when excessive innate immune function, such as the massive release of IFN-γ and TNF-α, is activated without infection. In relation to inflammatory liver injury, we hypothesized that Toxoplasma gondii inhibitor of STAT1 transcription (TgIST) can inhibit the inflammatory response induced by activating the STAT1/IRF-1 mechanism in liver inflammation. This study used IFN-γ and TNF-α as inflammatory inducers at the cellular level of murine hepatocytes (Hepa-1c1c7) to determine whether TgIST inhibits the STAT1/IRF-1 axis. In stable cells transfected with TgIST, STAT1 expression decreased with a decrease in interferon regulatory factor (IRF)-1 levels. Furthermore, STAT1 inhibition of TgIST resulted in lower levels of NF-κB and COX2, as well as significantly lower levels of class II transactivator (CIITA), iNOS, and chemokines (CLXCL9/10/11). TgIST also significantly reduced the expression of hepatocyte proapoptotic markers (Caspase3/8/9, P53, and BAX), which are linked to sterile inflammatory liver injury. TgIST also reduced the expression of adhesion (ICAM-1 and VCAM-1) and infiltration markers of programmed death-ligand 1 (PD-L1) induced by hepatocyte and tissue damage. TgIST restored the cell apoptosis induced by IFN-γ/TNF-α stimulation. These results suggest that TgIST can inhibit STAT1-mediated inflammatory and apoptotic responses in hepatocytes stimulated with proinflammatory cytokines.

• BMB Reports
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• v.45 no.3
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• pp.171-176
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• 2012

Receptor activator of NF-${\kappa}B$ ligand (RANKL) triggers the differentiation of bone marrow-derived monocyte/macrophage precursor cells (BMMs) of hematopoietic origin into osteoclasts through the activation of mitogen-activated protein (MAP) kinases and transcription factors. Recently, reactive oxygen species (ROS) and antioxidant enzymes were shown to be closely associated with RANKL-mediated osteoclast differentiation. Although glutaredoxin2 (Glrx2) plays a role in cellular redox homeostasis, its role in RANKL-mediated osteoclastogenesis is unclear. We found that Glrx2 isoform b (Glrx2b) expression is induced during RANKLmediated osteoclastogenesis. Over-expression of Glrx2b strongly enhanced RANKL- mediated osteoclastogenesis. In addition, Glrx2b-transduced BMMs enhanced the expression of key transcription factors c-Fos and NFATc1, but pre-treatment with SB203580, a p38-specific inhibitor, completely blocked this enhancement. Conversely, down-regulation of Glrx2b decreased RANKL- mediated osteoclastogenesis and the expression of c-Fos and NFATc1 proteins. Also, Glrx2b down-regulation attenuated the RANKL-induced activation of p38. Taken together, these results suggest that Glrx2b enhances RANKL-induced osteoclastogenesis via p38 activation.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.683-692
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• 2004

Curcumin (diferuloylmethane) is a major naturally-occurring polyphenol of Curcuma species, which is commonly used as a yellow coloring and flavoring agent in foods. Curcumin has shown anti-carcinogenic activity in animal models. Curcumin possesses anti-inflammatory activity and is a potent inhibitor of reactive oxygen-generating enzymes such as lipoxygenase/cyclooxygenase, xanthine dehydrogenase/oxidase and inducible nitric oxide synthase; and an effective inducer of heme oxygenase-1. Curcumin is also a potent inhibitor of protein kinase C(PKC), EGF(Epidermal growth factor)-receptor tyrosine kinase and LĸB kinase. Subsequently, curcumin inhibits the activation of NF(nucleor factor)KB and the expressions of oncogenes including c-jun, c-fos, c-myc, NIK, MAPKs, ERK, ELK, PI3K, Akt, CDKs and iNOS. It is proposed that curcumin may suppress tumor promotion through blocking signal transduction path-ways in the target cells. The oxidant tumor promoter TPA activates PKC by reacting with zinc thiolates present within the regulatory domain, while the oxidized form of cancer chemopreventive agent such as curcumin can inactivate PKC by oxidizing the vicinal thiols present within the catalytic domain. Recent studies indicated that proteasome-mediated degradation of cell proteins playa pivotal role in the regulation of several basic cellular processes including differentiation, proliferation, cell cycling, and apoptosis. It has been demonstrated that curcumin-induced apoptosis is mediated through the impairment of ubiquitin-proteasome pathway. Curcumin was first biotransformed to dihydrocurcumin and tetrahydrocurcumin and that these compounds subsequently were converted to monoglucuronide conjugates. These results suggest that curcumin-glucuronide, dihydrocurcumin-glucuronide, tetrahydrocurcumin-glucuronide and tetrahydrocurcumin are the major metabolites of curcumin in mice, rats and humans.

• Biomolecules & Therapeutics
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• v.22 no.4
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• pp.295-300
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• 2014

The actin cytoskeleton plays an important role in macrophage-mediated inflammatory responses by modulating the activation of Src and subsequently inducing nuclear factor (NF)-${\kappa}B$ translocation. In spite of its critical functions, few papers have examined how the actin cytoskeleton can be regulated by the activation of toll-like receptor (TLR). Therefore, in this study, we further characterized the biological value of the actin cytoskeleton in the functional activation of macrophages using an actin cytoskeleton disruptor, cytochalasin B (Cyto B), and explored the actin cytoskeleton's involvement in morphological changes, cellular attachment, and signaling events. Cyto B strongly suppressed the TLR4-mediated mRNA expression of inflammatory genes such as cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-${\alpha}$, and inducible nitric oxide (iNOS), without altering cell viability. This compound also strongly suppressed the morphological changes induced by lipopolysaccharide (LPS), a TLR4 ligand. Cyto B also remarkably suppressed NO production under non-adherent conditions but not in an adherent environment. Cyto B did not block the co-localization between surface glycoprotein myeloid differentiation protein-2 (MD2), a LPS signaling glycoprotein, and the actin cytoskeleton under LPS conditions. Interestingly, Cyto B and PP2, a Src inhibitor, enhanced the phagocytic uptake of fluorescein isothiocyanate (FITC)-dextran. Finally, it was found that Cyto B blocked the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) at 1 min and the phosphorylation of heat shock protein 27 (HSP27) at 5 min. Therefore, our data suggest that the actin cytoskeleton may be one of the key components involved in the control of TLR4-mediated inflammatory responses in macrophages.

• International Journal of Oral Biology
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• v.34 no.2
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• pp.87-95
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• 2009

Porphyromonas gingivalis is a major etiologic agent of chronic periodontitis and cytokines produced by macrophages play important roles in the pathogenesis of periodontal diseases. In this study we investigated the cytokine response of phorbol myristate acetatedifferentiated THP-1 cells exposed to P. gingivalis. Compared with the prominent cell wall components of P. gingivalis (lipopolysaccharide and the major fimbrial protein FimA), live P. gingivalis stimulated much higher levels of cytokine production. In addition, whereas low multiplicity of infection challenges (MOI=10) of P. gingivalis 381 stimulated high levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-6 (IL-6), and IL-1${\beta}$, high dose challenges with this bacterium (MOI = 100) resulted in a substantially diminished production of MCP-1 and IL-6. Moreover, high MOI P. gingivalis challenges achieved only low levels of induction of MCP-1 and IL-6 mRNA. The decreased production of MCP-1 and IL-6 appeared to be mediated by P. gingivalis proteases, because high MOI challenges with congenic protease mutant strains of this microorganism (MT10 and MT10W) did not result in a diminished production of MCP-1 and IL-6. Similar to its protease mutant strains, leupeptin (a protease inhibitor)- treated P. gingivalis at high doses induced high levels of MCP-1 production. To examine the mechanisms underlying the diminished production of MCP-1 by P. gingivalis proteases, the activation of mitogen-activated protein (MAP) kinases and NF-${\kappa}$B was compared between the 381 and MT10W strains. Whilst high doses of both 381 and MT10W similarly activated the three members of the MAP kinase family, the DNA binding activity of NF-${\kappa}$B, as revealed by gel shift assays, was greatly increased only by MT10W. Taken together, our data indicate that P. gingivalis stimulates the production of high levels of TNF-${\alpha}$, IL-1${\beta}$, IL-6, and MCP-1 but that high dose challenges with this bacterium result in a diminished production of MCP-1 and IL-6 via the protease-mediated suppression of NF-${\kappa}$B activation in THP-1 macrophagic cells.

• BMB Reports
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• v.46 no.9
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• pp.448-453
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• 2013

CpG-DNA has various immunomodulatory effects in dendritic cells, B cells, and macrophages. While induction of cytokines by CpG-DNA has been well documented in macrophages, the expression of costimulatory molecules in CpG-DNA treated macrophages has not yet been defined. Therefore, we investigated the effects of CpG-DNA on the expression of costimulatory molecules in RAW 264.7 cells. The surface expression of CD80 was slightly increased and CD83 expression was significantly increased in response to CpG-DNA. However, the expression of CD86 and MHC class II was not changed. As expression of CD83 mRNA was also increased by CpG-DNA, CD83 expression is regulated at a transcriptional level. To understand the contribution of signaling pathways to CD83 induction, we used pathway specific inhibitors. The NF-${\kappa}B$ inhibitor significantly reduced surface expression of CD83 as well as phagocytic activity of RAW 264.7 cells. Therefore, CD83 expression may contribute to the immunostimulatory effects of CpG-DNA in macrophage cells.