Dong-Joo Kwon

Hallym University, Sŏul, Seoul, South Korea

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Publications (22)26.82 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: HIV-1 Tat causes extensive neuroinflammation that may progress to AIDS-related encephalitis and dementia. Celastrol possesses various biological activities such as anti-oxidant, anti-tumor, and anti-inflammatory activities. In this study, we investigated the modulatory effects of celastrol on HIV-1 Tat-induced inflammatory responses and the molecular mechanisms underlying its action in astrocytes. Pre-treatment of CRT-MG human astroglioma cells with celastrol significantly inhibited HIV-1 Tat-induced expression of ICAM-1/VCAM-1 and subsequent monocyte adhesiveness in CRT-MG cells. In addition, celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory chemokines, such as CXCL10, IL-8, and MCP-1. Celastrol decreased HIV-1 Tat-induced activation of JNK MAPK, AP-1, and NF-κB. Furthermore, celastrol induced mRNA and protein expression of HO-1 as well as Nrf2 activation. Blockage of HO-1 expression using siRNA reversed the inhibitory effect of celastrol on HIV-1 Tat-induced inflammatory responses. These results suggest that celastrol has regulatory effects on HIV-1 Tat-induced inflammatory responses by blocking the JNK MAPK-AP-1/NF-κB signaling pathways and inducing HO-1 expression in astrocytes.
    Toxicology and Applied Pharmacology 07/2014; · 3.98 Impact Factor
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    ABSTRACT: We isolated the phenolic glucoside salicortin from a Populus euramericana bark extract, and examined its ability to suppress inflammatory responses as well as the molecular mechanisms underlying these abilities, using lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Salicortin inhibited iNOS expression and the subsequent production of NO in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Salicortin significantly suppressed LPS-induced signal cascades of NF-κB activation, such as IKK activation, IκBα phosphorylation and p65 phosphorylation in RAW 264.7 cells. In addition, salicortin inhibited the LPS-induced activation of JNK, but not ERK or p38 MAPK. Furthermore, salicortin significantly inhibited production of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6 in the LPS-stimulated RAW 264.7 cells. These findings suggest that salicortin may show its anti-inflammatory activity by suppressing the LPS-induced expression of pro-inflammatory mediators through inhibition of NF-κB and JNK MAPK signaling cascades in macrophages.
    BMB reports 12/2013; · 1.63 Impact Factor
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    ABSTRACT: Adhesion molecules such as ICAM-1 are important in the infiltration of leukocytes into the site of inflammation. In this study, we investigated the inhibitory effects of curcumin on ICAM-1 expression and monocyte adhesiveness as well as its underlying action mechanism in the TNF-α-stimulated keratinocytes. Curcumin induced expression of heme oxygenase-1 (HO-1) in the human keratinocyte cell line HaCaT. In addition, curcumin induced Nrf2 activation in dose- and time-dependent manners in the HaCaT cells. Curcumin suppressed TNF-α- induced ICAM-1 expression and subsequent monocyte adhesion, which were reversed by the addition of tin protoporphyrin IX (SnPP), a specific inhibitor of HO-1, or HO-1 knockdown using siRNA. Furthermore, Nrf2 knockdown using siRNA reversed the inhibitory effect of curcumin on the TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that curcumin may exert its anti-inflammatory activity by suppressing the TNF-α-induced ICAM-1 expression and subsequent monocyte adhesion via expression of HO-1 in the keratinocytes. [BMB Reports 2013; 46(8): 410-415].
    BMB reports 08/2013; 46(8):410-5. · 1.63 Impact Factor
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    ABSTRACT: Flavokawain A, a major constituent of chalcones derived from kava extracts, exerts various biological activities such as anti-tumor activities. In this study, we examined the suppressive effect of flavokawain A on LPS-induced expression of pro-inflammatory mediators and the molecular mechanisms responsible for these activities in the murine macrophages. Flavokawain A significantly suppressed expression of iNOS and COX-2, as well as the subsequent production of NO and PGE2 in the LPS-stimulated RAW 264.7 cells. Flavokawain A significantly inhibited LPS-induced activation of NF-κB and AP-1 signaling pathways. In addition, flavokawain A inhibited activation of JNK and p38 MAPK which was responsible for expression of iNOS and COX-2 in the LPS-stimulated RAW 264.7 cells. Furthermore, flavokawain A suppressed LPS-induced expression of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6. These results suggest that flavokawain A may exert anti-inflammatory responses by suppressing LPS-induced expression of pro-inflammatory mediators via blockage of NF-κB-AP-1-JNK/p38 MAPK signaling pathways in the murine macrophages.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 05/2013; · 2.99 Impact Factor
  • Dong-Joo Kwon, Young-Soo Bae
    Chemistry of Natural Compounds 01/2013; 49(1). · 0.60 Impact Factor
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    ABSTRACT: Defensins, a family of antimicrobial peptides, are one of the first lines of host defense. Human beta-defensins (hBD) such as hBD-2 and -3 have anti-HIV activity. Previous studies have shown that HIV-1 virion can induce the expression of hBD, although the exact components of HIV-1 virion that are responsible for hBD expression have not yet been elucidated. In this study, we examined the effect of HIV-1 Tat on the expression of hBD in B cells. Stimulation of B cells with HIV-1 Tat protein significantly increased the mRNA and protein levels of hBD-2. HIV-1 Tat also induced the activation of a reporter gene for hBD-2 in a dose-dependent manner in B cells. Pretreatment of B cells with a JNK inhibitor suppressed HIV-1 Tat-induced hBD-2 expression. Pretreatment of B cells with AP-1 inhibitors or NF-κB inhibitors led to a decrease in HIV-1 Tat-induced protein and mRNA expression of hBD-2. Taken together, our results indicate that HIV-1 Tat can up-regulate the expression of hBD-2 via JNK-NF-κB/AP-1-dependent pathways in human B cells.
    Molecules and Cells 03/2012; 33(4):335-41. · 2.21 Impact Factor
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    ABSTRACT: Casuarinin is a naturally occurring tannin that is isolated from the leaves of Hippophae rhamnoides. It has been shown to have anti-oxidant, anti-cancer, anti-viral, and anti-inflammatory activities. The aim of this study was to investigate the possible mechanism by which casuarinin inhibits TNF-α/IFN-γ-induced Th2 chemokines expression in the human keratinocytes cell line HaCaT. We found that casuarinin suppressed TNF-α/IFN-γ-induced expression of TARC and MDC mRNA and protein in HaCaT cells. Casuarinin significantly inhibited TNF-α/IFN-γ-induced activation of NF-κB, STAT1, and p38 MAPK. Furthermore, we observed that p38 MAPK contributes to inhibition of TNF-α/IFN-γ-induced TARC and MDC production by blocking NF-κB and STAT1 activation in HaCaT cells. Taken together, these results suggest that casuarinin may exert anti-inflammatory responses by suppressing TNF-α/IFN-γ-induced expression of TARC and MDC via blockage of p38 MAPK activation and subsequent activation of NF-κB and STAT1. We propose that it could therefore be used as a therapeutic agent against inflammatory skin diseases.
    Biochemical and Biophysical Research Communications 01/2012; 417(4):1254-9. · 2.28 Impact Factor
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    ABSTRACT: Up-regulation of selected matrix metalloproteinases (MMPs) such as MMP-9 contributes to inflammatory processes during the development of various skin diseases, such as atopic dermatitis. In this study, we examined the effect of a cell-permeable superoxide dismutase (Tat-SOD) on TNF-α-induced MMP-9 expression in human keratinocyte cells (HaCaT). When Tat-SOD was added to the culture medium of HaCaT cells, it rapidly entered the cells in dose- and time-dependent manners. Tat-SOD decreased TNF-α-induced reactive oxygen species (ROS) generation. Tat-SOD also inhibited TNF-α-induced NF-κB DNA binding activity. Treatment of HaCaT cells with Tat-SOD significantly inhibited TNF-α-induced mRNA and protein expression of MMP-9, as measured by RT-PCR and Western blot analysis. In addition, Tat-SOD suppressed TNF-α-induced gelatinolytic activity of MMP-9. Taken together, our results indicate that Tat-SOD can suppress TNF-α-induced MMP-9 expression via ROS-NF-κB-dependent mechanisms in keratinocytes, and therefore can be used as an immunomodulatory agent against inflammatory skin diseases related to oxidative stress.
    BMB reports 07/2011; 44(7):462-7. · 1.63 Impact Factor
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    ABSTRACT: Hippophae rhamnoides has been extensively used in oriental traditional medicines for treatment of asthma, skin diseases, gastric ulcers, and lung disorders. In this study, we isolated casuarinin from the leaves of H.rhamnoides and examined the effect of casuarinin on the TNF-α-induced ICAM-1 expression in a human keratinocytes cell line HaCaT. Pretreatment with casuarinin inhibited TNF-α-induced protein and mRNA expression of ICAM-1 and subsequent monocyte adhesiveness in HaCaT cells. Casuarinin significantly inhibited TNF-α-induced NF-κB activation. In addition, casuarinin inhibited activation of ERK and p38 MAPK in a dose-dependent manner. Furthermore, pretreatment with casuarinin decreased TNF-α-induced pro-inflammatory mediators, such as IL-1β, IL-6, IL-8, and MCP-1. These results demonstrated that casuarinin exerts its anti-inflammatory activity by suppressing TNF-α-induced expression of ICAM-1 and pro-inflammatory cytokines/chemokines via blockage of activation of NF-κB and ERK/p38 MAPK and can be used as a therapeutic agent against inflammatory skin diseases.
    Biochemical and Biophysical Research Communications 06/2011; 409(4):780-5. · 2.28 Impact Factor
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    ABSTRACT: We previously demonstrated that celastrol, a quinone methide triterpenoid derived from the medicinal plant Tripterygium wilfordii, exerts its anti-inflammatory activity through up-regulation of heme oxygenase-1 (HO-1) expression in the keratinocytes. In this study, we examined the signaling pathways that lead to the up-regulation of HO-1 expression by celastrol. In HaCaT cells, celastrol-induced HO-1 expression was dependent on ROS generation. ERK and p38 MAPK were major MAPK pathways responsible for celastrol-induced HO-1 expression. Celastrol induced Nrf2 activation. Nrf2 knockdown using small interfering RNA (siRNA) inhibited celastrol-induced HO-1 expression. Treatment with celastrol resulted in a marked increase in antioxidant response element (ARE)-driven transcriptional activity, which was dependent on ROS generation and activation of ERK and p38 MAPK. Furthermore, Nrf2 siRNA significantly reversed the inhibitory effect of celastrol on IFN-γ-induced expression of ICAM-1 in the keratinocytes. Taken together, our results indicate that celastrol can activate the ROS-ERK/p38-Nrf2-ARE signaling cascades leading to the up-regulation of HO-1 which is partly responsible for its anti-inflammatory activity in the keratinocytes.
    Biochemical and Biophysical Research Communications 03/2011; 407(3):535-40. · 2.28 Impact Factor
  • Dong-Joo Kwon, Young-Soo Bae
    Chemistry of Natural Compounds 01/2011; 47(4):636-638. · 0.60 Impact Factor
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    Dong-Joo Kwon, Jin-Kyu Kim, Young-Soo Bae
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    ABSTRACT: There have been few reports on the constituents and biological activity of stem bark of , and no phytochemical and biological studies have been reported for stem wood of . Two flavan 3-ols (1 and 2), three phenolic acid/alcohols (3~5), and two coumarins (6 and 7) were isolated from the stem wood of by repeated column chromatography. The structure of isolated compounds were identified as (+)-catechin (1), (-)-epicatechin (2), -hydroxybenzaldehyde (3), syringic alcohol (4), -tyrosol (5), scopoletin (6), and cleomiscosin A (7) on the basis of spectroscopic evidences such as -NMR, -NMR, 2D-NMR and MS spectrum. -Hydroxybenzaldehyde (3), syringic alcohol (4), scopoletin (6), and cleomiscosin A (7) have not been reported from this plant so far. (+)-Catechin (1) and (-)-epicatechin (2) showed the higher 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than butylated hydroxyanisole (BHA) used as a positive control.
    Journal of the Korean Wood Science and Technology. 01/2011; 39(1).
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    ABSTRACT: Ulmus davidiana var. japonica is a deciduous tree used in traditional medicine. In this study, we examined the antioxidant and anti-inflammatory activity of extracts and compounds isolated from U. davidiana var. japonica stem barks for development of cosmetic phyto-materials. Phytochemical examination of the stem bark led to the isolation and characterization of three known compounds, (+)-catechin (1), (+)-catechin-7-O--D-apiofuranoside (2), and procyanidin B3 ((+)-catechin-()-(+)-catechin) (3). Their bioactivities including antioxidant (DPPH ree radical scavenging assay) activity, anti-inflammatory (nitric oxide nhibition assay) were evaluated. Most of the crude extracts and isolates indicated significant antioxidant potential compared with BHT and -tocopherol as controls. Futhermore, all compounds showed higher inhibitory activities for NO production in Raw 264.7 cells than the L-NMMA using the positive control. Eespecially, (+)-catechin (1) and (+)-catechin-7-O--D-apiofuranoside (2) which could inhibit more than 90% of the NO production at a concentration of 100 , implying excellent anti-inflammatory activity.
    Journal of the Korean Wood Science and Technology. 01/2010; 38(5).
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    ABSTRACT: Keratinocytes, one of major cell types in the skin, can be induced by TNF-alpha and IFN-gamma to express thymus- and activation-regulated chemokine (TARC/CCL17), which is considered to be a pivotal mediator in the inflammatory responses during the development of inflammatory skin diseases, such as atopic dermatitis (AD). In this study, we examined the effect of 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG), isolated from the barks of Juglans mandshurica, on TNF-alpha/IFN-gamma induced CCL17 expression in the human keratinocyte cell line HaCaT. Pretreatment of HaCaT cells with PGG suppressed TNF-alpha/IFN-gamma-induced protein and mRNA expression of CCL17. PGG significantly inhibited TNF-alpha/IFN-gamma-induced NF-kappaB activation as well as STAT1 activation. Furthermore, pretreatment with PGG resulted in significant reduction in expression of CXCL9, 10, and 11 in the HaCaT cells treated with IFN-gamma. These results suggest that PGG may exert anti-inflammatory responses by suppressing TNF-alpha and/or IFN-gamma-induced activation of NF-kappaB and STAT1 in the keratinocytes and might be a useful tool in therapy of skin inflammatory diseases.
    Biochemical and Biophysical Research Communications 10/2009; 387(1):115-20. · 2.28 Impact Factor
  • Dong-Joo Kwon, Young-Soo Bae
    Biochemical Systematics and Ecology - BIOCHEM SYST ECOL. 01/2009; 37(1):46-48.
  • Holzforschung 01/2009; 63(4):440-442. · 2.42 Impact Factor
  • Dong-Joo Kwon, Young-Soo Bae
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    ABSTRACT: The bark of Acer barbinerve was extracted with 70% aqueous acetone and the organic extracts were concentrated to small volume using rotary evaporator and then fractionated successively with n-hexane, dichloromethane, ethyl acetate and water. The chromatographic separation of ethyl acetate soluble fraction led to the isolation of five phenolic compounds. By means of spectroscopic method, the structures of these compounds were identified to methyl gallate (1), methyl gallate-4-O--D-glucose (2), (+)-catechin (3), (-)-epicatechin (4) and (-)-epicatechin-3-O-gallate (5). These compounds (1-5) have not been reported in this plant yet.
    Journal of the Korean Wood Science and Technology. 01/2009; 37(2).
  • Dong-Joo Kwon, Young-Soo Bae
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    ABSTRACT: The chemical constituents of Acer komarovii Pojark. which belongs to Aceraceae has never been reported. The bark of A. komarovii was extracted with 70% aqueous acetone, and the concentrated extract was successively partitioned with n-hexane, dichloromethane, ethyl acetate and . From the ethyl acetate soluble fraction, four compounds were isolated by the repeated Sephadex LH-20 and RP C-18 column chromatography. From the results of spectroscopic methods including FAB-MS, 1D and 2D NMR, the structures of the compounds were determined as quercetin (1), guaijaverin (2), hirsutrin (3) and hyperin (4). These compounds (1-4) have not been reported in this tree yet.
    Journal of the Korean Wood Science and Technology. 01/2009; 37(2).
  • Dong-Joo Kwon, Young-Soo Bae
    Biochemical Systematics and Ecology - BIOCHEM SYST ECOL. 01/2009; 37(2):130-132.
  • Dong-Joo Kwon, Young-Soo Bae
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    ABSTRACT: Juglans mandshurica bark was collected and extracted with 70% aqueous acetone. The extracts were concentrated and then sequentially fractionated using n-hexane, , EtOAc, and to be freeze dried. A portion of fraction was chromatographed on a Sephadex LH-20 column using aqueous methanol to isolate (S)-2,3-HHDP-D-glucopyranoside (1). Some of EtOAc fraction was also treated on a Sephadex LH-20 column using aqueous methanol and EtOH-hexane mixture to purify pedunculagin (2). The structures of these two epimeric ellagitannins were elucidated by spectroscopic tools, NMR and MS.
    Journal of the Korean Wood Science and Technology. 01/2009; 37(5).

Publication Stats

69 Citations
26.82 Total Impact Points

Institutions

  • 2009–2014
    • Hallym University
      Sŏul, Seoul, South Korea
  • 2009–2011
    • Kangwon National University
      • • Department of Forest Biomaterials Engineering
      • • College of Forest and Environmental Science
      Gangneung, Gangwon, South Korea