Eui-Hong Byun

Gamma-irradiated resveratrol negatively regulates LPS-induced MAPK and NF-κB signaling through TLR4 in macrophages

Resveratrol was irradiated at various doses of 15, 30, 50, and 70kGy for the development of physiological functionalities through modification of the structural properties. Gamma irradiation induced a decrease in the resveratrol peak, and the appearance of several new peaks by gamma irradiation was gradually increased up to 70kGy. Gamma-irradiated resveratrol did not exert cytotoxicity to macrophages in dose ranges from 15 to 70kGy; therefore, 70kGy gamma-irradiated resveratrol was used as the maximum dose throughout subsequent experiments. Treatment of LPS-stimulated macrophages with 70kGy gamma-irradiated resveratrol resulted in a dose-dependent decrease in iNOS-mediated NO, PGE2, and pro-inflammatory cytokine level, such as TNF-α, IL-6 and IL-1β. 70kGy gamma-irradiated resveratrol significantly inhibited cyclooxygenase-2 levels, as well as the expression of cell surface molecules, such as CD80 and CD86, in LPS-induced macrophages. Furthermore, the inhibitory action of these pro-inflammatory mediators occurred through an inhibition of MAPKs (ERK1/2, p38 and JNK) and NF-κB signaling pathways based on a toll-like receptor 4 in macrophages, which may be closely mediated with the radiolysis products of resveratrol transformed by gamma-irradiation. From these findings, it seems likely that gamma irradiation can be an effective tool for a reduction of the toxicity and play a potent role in the treatment of inflammatory disease.

Epigallocatechin-3-gallate-mediated Tollip induction through the 67-kDa laminin receptor negatively regulating TLR4 signaling in endothelial cells.

BACKGROUND Green tea polyphenol epigallocatechin-3-gallate (EGCG) has the potential to impact a variety of inflammation-related diseases; however, the anti-inflammatory action of EGCG in endothelial cells has not been understood. Recently, we demonstrated that the 67-kDa laminin receptor (67LR) acts as a cell-surface EGCG receptor. AIM This research was carried out to clarify the molecular basis for the down-regulation of toll-like receptor 4 (TLR4) signal transduction by EGCG in lipopolysaccharide (LPS)-stimulated endothelial cells. RESULTS RNAi-mediated silencing of 67LR resulted in an abrogation of the inhibitory action of EGCG on the LPS-induced activation of downstream signaling pathways. Also, we found that EGCG induced a rapid upregulation of Toll-interacting protein (Tollip), a negative regulator of TLR signaling, through 67LR in endothelial cells. RNAi-mediated silencing of Tollip impaired the TLR4 signaling inhibitory activity of EGCG. Additionally, silencing of Tollip resulted in an abrogation of the inhibitory action of EGCG on the LPS-induced expressions of cell-associated adhesion molecules, such as ICAM-1 and VCAM-1. CONCLUSION Taken together, these novel findings provide new insights into an understanding of negative regulatory mechanisms of the TLR4 signaling pathway and effective therapeutic intervention for the treatment of inflammatory disease.

Gamma-irradiated β-glucan induces immunomodulation and anticancer activity through MAPK and NF-κB pathways

BACKGROUND This study was designed to evaluate the antitumor activity of low-molecular-weight β-glucan (LMBG) produced by gamma irradiation (50 kGy), using in vivo and in vitro models. RESULTS The results indicate that treatment with LMBG increased the proliferation of murine peritoneal macrophages, and their production of tumor necrosis factor α and nitric oxide, to a greater extent than treatment with high-molecular-weight β-glucan (HMBG). The activation of peritoneal macrophages by LMBG was mediated by both mitogen-activated protein kinases and nuclear factor-κB signaling. Interestingly, when administered prophylactically, LMBG significantly inhibited tumor growth and lung metastasis in mice injected with B16BL6 melanoma cells compared with the HMBG-treated group. In comparison with HMBG treatment, LMBG treatment also elevated cell proliferation, cytokine (interferon-γ and interleukin-2) production, and CD8(+) T cell populations in splenocytes from tumor-bearing mice. CONCLUSION These data indicate that LMBG is important in eliciting antitumor activity through a non-specific immune response and may play a major role as a value-added product in the medical industry.

Gamma-irradiated black ginseng extract inhibits mast cell degranulation and suppresses atopic dermatitis-like skin lesions in mice

Gamma irradiation is able to affect various structural modification and an increase of the biological properties of biomaterials. This study was conducted to investigate the anti-allergenic effect of γ-irradiated black ginseng extract (BGE) using in vitro and in vivo experiments. IgEantigen complex-induced degranulation was measured in RBL-2H3 mast cells. In addition, an anti-atopic dermatitis (AD) test was carried out by spreading γ-irradiated BGE on the dorsal skin of 2,4-dinitrochlorobenzene (DNCB)-induced BALB/c mice. The content of arginylfructose (AF) of gamma-irradiated BGE was higher than that of BGE. In RBL-2H3 mast cells, γ-irradiated BGE treatments significantly reduced the IgE-antigen complex-induced release of β-hexosaminidase, histamine, intracellular ROS, and Ca2+ influx. A western blot analysis showed that γ-irradiated BGE had an inhibitory activity on the FcεRI-mediated signaling in mast cells. In the DNCB-induced AD model, γ-irradiated BGE significantly alleviated the ADlike skin symptoms and clinical signs. The suppression of AD by γ-irradiated BGE was accompanied by a decrease in the serum level of IgE and IL-4, as well as the number of leukocyte. Gamma-irradiated BGE also suppressed IL-4 and increased IFN-γ in splenocytes. Our data suggests that γ-irradiated BGE may be effective therapeutic agents for the treatment of AD.

β-(1,3)-Glucan Isolated from Agrobacterium Species Induces Maturation of Bone Marrow-derived Dendritic Cells and Drives Th1 Immune Responses

The β-(1,3)-glucan originally isolated from Agrobacterium species was investigated for prompting maturation of dendritic cells (DCs) and driving Th1 immune responses. Bone-marrow derived DCs separated from mice were analyzed for augmentation of cell surface molecule (CD80, CD86, and major histo-compatability complex (MHC) class I/II) expression and pro-inflammatory cytokine production (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6). β-Glucan functionally induced DCs activation via augmentation of CD80, CD86, and MHC class I/II expression and cytokine production (TNF-α, IL-1β, and IL-6). β-Glucan induced secretion of IL-12p70, but not IL-10. Both mitogen-activated protein kinases and nuclear factor (NF)-κB signaling mediated production of pro-inflammatory cytokine induced by β-glucan. β-Glucan-treated DCs exhibited accelerated proliferation of murine splenocytes with increased levels of interferon (IFN)-γ. β-Glucan regulates innate and adaptive immunity via DCs activation and Th1 polarization of immune responses.

Gamma irradiation enhanced Tollip-mediated anti-inflammatory action through structural modification of quercetin in lipopolysaccharide-stimulated macrophages

Abstract The changes in molecular structure and anti‐inflammatory action of a gamma‐irradiated quercetin were examined. Quercetin was gamma‐irradiated at doses of 0, 15, 30, 50, 100 and 150 kGy, which induced new radiolytic peaks (the highest radiolytic peak at a dose of 30 kGy). Treatment of intact‐ and gamma‐irradiated quercetin did not induce a significant cellular toxicity of macrophages at concentrations ranging from 12.5 to 50 &mgr;M. Treatment of LPS‐stimulated macrophages with gamma‐irradiated quercetin (30 kGy) showed a higher inhibitory action than intact‐quercetin groups in the excessive expression of inducible nitric oxide synthases‐mediated nitric oxide, prostaglandin E2, pro‐inflammatory cytokines level, such as tumor necrosis factor‐&agr;, interleukin‐6 and interleukin‐1&bgr;, reactive oxygen species, as well as cell surface molecules (CD80, CD86, and MHC class I/II). The inhibition of LPS‐stimulated pro‐inflammatory mediators was mediated through a suppression of mitogen‐activated protein kinases and nuclear factor‐&kgr;B pathways. In addition, gamma‐irradiated quercetin (30 kGy) markedly elevated the expression of the Toll‐interacting protein compared to intact‐quercetin. The inhibitory action of intact‐ and gamma‐irradiated quercetin on the production of IL‐6 and TNF‐&agr; was not observed in the down‐regulation of Tollip. Therefore, these findings represent new insights into the understanding of the changes in molecular structure and the physiological properties of natural products through the application of radiation technology. HighlightsGamma‐irradiation induced structural modification of quercetin.Gamma‐irradiated quercetin inhibited the pro‐inflammatory mediators.Gamma‐irradiated quercetin induced an inhibition of MAPKs and NF‐&kgr;B.Gamma‐irradiated quercetin enhanced Tollip‐mediated anti‐inflammation.

Improved reutilization of industrial crude lysine to 1,5-diaminopentane by enzymatic decarboxylation using various detergents and organic solvents

World-wide production of l-lysine has rapidly increased in recent years. In the industrial scale production, it is cost effective to minimize waste as many waste materials are generated during downstream processing. Therefore, the conversion of crude lysine to a more valuable product reduces waste emission. In this study, 1,5-diaminopentane (DAP, trivial name: cadaverine) was produced by l-lysine decarboxylation using Hafnia alvei. The conditions of enzymatic reaction were determined. In particular, the addition of specific detergent (Brij 56) was significantly affected in the bioconversion system. Addition of hydrophobic organic solvent improved the mixing of the reactants. Finally, an industrial crude form of lysine served as a substrate. The DAP conversion by analytical, feed and industrial crude l-lysine was 93.9%, 90.3%, and 63.8%, respectively.

Gamma irradiation of aloe-emodin induced structural modification and apoptosis through a ROS- and caspase-dependent mitochondrial pathway in stomach tumor cells

Abstract Purpose: The changes in molecular structure and the physiological properties of a gamma-irradiated aloe-emodin were examined. Materials and methods: Aloe-emodin was gamma-irradiated at doses ranging from 0 to 150 kGy, and the molecular structure was then analyzed using high-performance liquid chromatography (HPLC). AGS cells were cultured in RPMI medium and treated gamma irradiated aloe-emodin. Cell viability was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Apoptosis efficiency was investigated by cell cycle arrest, cell morphology, and signaling pathway. The structure of new radiolytic peak was identified by the hydrogen-nuclear magnetic resonance (1H NMR). Results: HPLC results showed that gamma irradiation induced new radiolytic peaks that were distinguishable from the aloe-emodin standard, and the area of new peaks was increased as the radiation dose increased. Gamma-irradiated aloe-emodin treatment significantly increased the cytotoxicity in AGS tumor cells. We also found that 150 kGy aloe-emodin increased the expression of Bax, cytosolic cytochrome c, PARP cleavage, and the activation of caspases-8, -9, -3, Bid, and Bcl-2. Treatment of 150 kGy aloe-emodin induced ROS production, DNA fragmentation, alterations of cell morphology, and the migration in AGS cells. Gamma-irradiated aloe-emodin induced an increase of sub-G1 phase and depolarization of mitochondrial membrane potential in AGS cells. We also confirmed that fractionated AEF1 (new radiolytic peak) induce the cell death, migration, an increase of sub-G1 phase and cytochrome c in a ROS-dependent manner. Conclusions: The radiolysis product (AEF1) of aloe-emodin transformed by gamma-irradiation strongly induced apoptotic cell death in AGS cells, indicating AEF1 is a potential candidate drug for use in anti-cancer drug.

Neuroprotective effect of polysaccharide separated from Perilla frutescens Britton var. acuta Kudo against H2O2-induced oxidative stress in HT22 hippocampus cells

ABSTRACT This study was carried out to evaluate the neuroprotective activity of polysaccharide extracts isolated from Perilla frutescens (PEPF) in H2O2-treated HT22 hippocampus cells. The PEPF treatment was found to increase the anti-oxidant activities of HT22 hippocampus cells. PEPF treatment resulted in a significant protection of HT22 hippocampus cells against H2O2-induced neurotoxicity, this protection ultimately occurred through an inhibition of ROS-mediated intracellular Ca2+ levels leading to MAPKs and NF-κB, as well as the accumulation of PI3K/AKT and Nrf2-mediated HO-1/NQO1 pathways. Furthermore, PEPF not only decreased the expression of Bax, cytochrome c, and cleaved caspases-3, -8, and -9, but also increased the expression of PARP and Bcl-2 in the H2O2-treated HT22 hippocampus cells, which overall contributed to the neuroprotective action. PEPF retains its mitochondrial membrane potential and reduces the elevated levels of sub-G1 phase and apoptotic morphological features induced by H2O2. It also reduces the malondialdehyde levels and enhances the intracellular SOD activity. Neuroprotective effect of PEPF against H2O2-induced oxidative stress in HT22 hippocampus cells.