• YAKHAK HOEJI
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• v.35 no.3
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• pp.154-164
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• 1991

These experiments were conducted to investigate the effects of Glycyrrhizae Radix extract(GR) on histamine synthesis, lymphocyte blastogenesis in C57BL/6J mice splenocytes, IL-1 production, $Ca^{2+}$ uptake by macrophage-like P388D$_{1}$ cells and plaque forming cell assay against SRBC. Histamine contents, lymphocyte blastogenesis, IL-1 activity, $Ca^{2+}$ uptake and plaque forming cell were determined by enzyme isotope method, [$^{3}$H]-thymidine incorporation, C3H/HeJ mouse thymocytes proliferation, the addition of 5 $\mu$Ci/ml $^{45}Ca^{2+}$ to P388D$_{1}$ cell suspension and assay to sheep red blood cell, respectively. Cytotoxicity, which was expressed as 50% mortality, was occurred by the addition of GR(10$^{-3}$g/ml). Histamine production in mouse spleen cell culture was significantly increased by 48 hour incubation added 0.25$\mu\textrm{g}$/ml of Con A. Con A-dependent T-lymphocyte proliferation was also enhanced by the addition of 0.25 $\mu\textrm{g}$/ml of Con A. GR depressed histamine contents at 10$^{-9}$~10$^{-4}$g/ml. and Con A (0.25 $\mu\textrm{g}$/ml) dependent T-lymphocyte proliferation at 10$^{-5}$~10$^{-4}$g/ml. IL-1 activity was significantly decreased by 10$^{-8}$~10$^{-4}$g/ml of GR. $Ca^{2+}$ uptake was not changed by GR, but antibody production markedly increased at 10.0~50.0 mg/kg of GR. From the above results, it is suggested that GR have immuno-regulatory action; GR decreased cell-mediated immune response and increased antibody production by B lymphocyte at high doses.

• Biomedical Science Letters
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• v.23 no.4
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• pp.327-332
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• 2017

A2B adenosine receptor (A2BAR) is known to be a regulator of bone homeostasis, but the regulatory mechanism of A2BAR on the osteoclast proliferation are poorly explored. Recently, we have shown that stimulation with BAY 60-6583, a specific agonist of A2BAR, significantly reduced macrophage-colony stimulating factor (M-CSF)-induced osteoclast proliferation by inducing cell cycle arrest at G1 phase and increasing the apoptosis of osteoclasts. The objective of this study was to investigate the regulatory mechanisms of cell cycle and apoptosis by A2BAR stimulation. The expression of A2BAR and M-CSF receptor, c-Fms, was not changed by A2BAR stimulation whereas M-CSF effectively induced c-Fms expression during osteoclast proliferation. Interestingly, A2BAR stimulation remarkably increased the expression of $p27^{Kip-1}$, a cell cycle inhibitor, but the expression of Cyclin D1 and cdk4 was not affected. In addition, while BAY 60-6583 treatment reduced the expression of Bcl2, an anti-apoptotic oncogene, it failed to regulate the expression of Bax, a pro-apoptotic marker. Taken together, these results imply that the increase of $p27^{Kip-1}$ inducing cell cycle arrest at G1 phase and the decrease of Bcl2 inducing anti-apoptotic response by A2BAR stimulation contribute to the down-regulation of osteoclast proliferation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1721-1724
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• 2013

Objective: To investigate the effect of epirubicin on soluble CD25 (sCD25) secretion by CD4+CD25+ regulatory T (Treg) cells isolated from diffuse large B-cell lymphoma (DLBCL) patients. Methods: Treg cells were isolated from the peripheral blood mononuclear cells isolated from the newly diagnosed DBLCL patients. The concentration of sCD25 in the supernatant was determined with a commercial sCD25 (IL-2R) enzyme-linked immunosorbent assay (ELISA) kit. The fluorescence intensity of CD25 was detected by flow cytometry. Results: Cell survival rate was significantly decreased along with the increase of epirubicin concentration after treatment for 24 h. There was also a significant difference in the concentration of sCD25 between the epirubicin group and the control group (P<0.01). A positive correlation between the Treg cells survival rate and the concentration of sCD25 was detected (r=0.993, P<0.01). When equal numbers of CD4+CD25+ Treg cells of the epirubicin group and the control group were cultured for another 24 h without epirubicin the CD25 fluorescence intensity on the surface of Treg cells was obviously higher in the epirubicin group than that in the control group (P<0.01), while the sCD25 concentration in the supernatant in the epirubicin group was significantly lower than that in the control group (P<0.05). Conclusion: Epirubicin may improve the body's immune functions by inhibiting the sCD25 secretion by Treg cells in DLBCL patients.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1620-1628
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• 2016

In this study, we investigated colistin resistance mechanisms associated with the regulation of the pbgP operon in Klebsiella pneumoniae, using four isogenic pairs of colistin-susceptible strains and their colistin-resistant derivatives and two colistin-resistant clinical isolates. Amino acid sequence alterations of PhoPQ, PmrAB, and MgrB were investigated, and mRNA expression levels of phoQ, pmrB, pmrD, and pbgP were measured using quantitative real-time PCR. The phoQ and pmrB genes were deleted from two colistin-resistant derivatives, 134R and 063R. We found that phoQ, pmrD, and pbgP were significantly upregulated in all colistin-resistant derivatives. However, pmrB was significantly upregulated in only two colistin-resistant derivatives and one clinical strain. pmrB was not overexpressed in the other strains. The minimum inhibitory concentration of colistin was drastically lower in both phoQ- and pmrB-deleted mutants from a colistin-resistant derivative (134R) that was overexpressing phoQ and pmrB. However, colistin susceptibility was restored only in a phoQ-deleted mutant from a colistin-resistant derivative (063R) without overexpression of pmrB. In conclusion, two different regulations of the pbgP operon may associate with the development of colistinresisant K. pneumoniae.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.375-382
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• 2012

Ginsenoside Rp1 (G-Rp1) is a saponin derivate that provides anti-metastatic activities through inhibition of the NF-${\kappa}B$ pathway. In this study, we examined the effects of G-Rp1 on regulatory T cell (Treg) activation. After treatment of splenocytes with G-Rp1, Tregs exhibited upregulation of IL-10 expression, and along with dendritic cells (DCs), these Tregs showed increased cell number compared to other cell populations. The effect of G-Rp1 on Treg number was augmented in the presence of lipopolysaccharide (LPS), which mimics pathological changes that occur during inflammation. However, depletion of DCs prevented the increase in Treg number in the presence of G-Rp1 and/or LPS. In addition, G-Rp1 promoted the differentiation of the memory types of $CD4^+Foxp3^+CD62L^{low}$ Tregs rather than the generation of new Tregs. In vivo experiments also demonstrated that Tregs and DCs from mice that were fed G-Rp1 for 7 d and then injected with LPS exhibited increased activation compared with those from mice that were injected with LPS alone. Expression of TGF-${\beta}$ and CTLA4 in Tregs was increased, and upregulation of IL-2 and CD80/CD86 expression by DCs affected the suppressive function of Tregs through IL-2 receptors and CTLA4. These data demonstrate that G-Rp1 exerts anti-inflammatory effects by activating Tregs in vitro and in vivo.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.130-139
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• 2017

$CXCR5^+$ T follicular helper (Tfh) cells are associated with aberrant autoantibody production in patients with antibody-mediated autoimmune diseases including lupus. Follicular regulatory T (Tfr) cells expressing CXCR5 and Bcl6 have been recently identified as a specialized subset of $Foxp3^+$ regulatory T (Treg) cells that control germinal center reactions. In this study, we show that retroviral transduction of CXCR5 gene in $Foxp3^+$ Treg cells induced a stable expression of functional CXCR5 on their surface. The Cxcr5-transduced Treg cells maintained the expression of Treg cell signature genes and the suppressive activity. The expression of CXCR5 as well as Foxp3 in the transduced Treg cells appeared to be stable in vivo in an adoptive transfer experiment. Moreover, Cxcr5-transduced Treg cells preferentially migrated toward the CXCL13 gradient, leading to an effective suppression of antibody production from B cells stimulated with Tfh cells. Therefore, our results demonstrate that enforced expression of CXCR5 onto Treg cells efficiently induces Tfr cell-like properties, which might be a promising cellular therapeutic approach for the treatment of antibody-mediated autoimmune diseases.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.189-193
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• 2005

IgE-dependent histamine-releasing factor(HRF) was initially described as a secretagogue for secretion of histamine from IgE+ basophils from a subset of allergic donors. Previously, we identified that S98 residue of HRF was phosphorylated using anti-HRFpS98 antibody which specifically recognizes the phosphorylated serine residue of HRF and HRFS98A mutant construct. In vitro kinase assay, only wild type HRF was phosphorylated by PKC, and S98A HRF was not affected by PKC. In this study, we attempted to characterize the phosphatase which specifically dephosphorylates HRF by immunoprecipitation and pull-down assay. In RBL-2H3 cells, HRF interacted only with calcineurin (also called as PP2B, calcium/calmodulin-dependent phosphatase) but not with PP1 or PP2A. The results suggest that HRF is most likely dephosphory-lated by calcineurin.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.384-389
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• 2014

Adiponectin, an adipokine predominantly secreted from adipose tissue, exhibits diverse biological responses, including metabolism of glucose and lipid, and apoptosis in cancer cells. Recently, adiponectin has been shown to modulate autophagy as well. While emerging evidence has demonstrated that autophagy plays a role in the modulation of proliferation and apoptosis of cancer cells, the role of autophagy in apoptosis of cancer cell caused by adiponectin has not been explored. In the present study, we demonstrated that globular adiponectin (gAcrp) induces both apoptosis and autophagy in human hepatoma cell line (HepG2 cells) and breast cancer cells (MCF-7), as evidenced by increase in caspase-3 activity, Bax, microtubule-associated protein light chain 3-II (LC3 II) protein levels, and autophagosome formation. Interestingly, gene silencing of LC3B, an autophagy marker, significantly enhanced gAcrp-induced apoptosis in both HepG2 and MCF-7 cell lines, whereas induction of autophagy by rapamycin, an mTOR inhibitor, significantly prevented gAcrp-induced apoptosis in hepatoma cells HepG2. Furthermore, modulation of autophagy produced similar effects on gAcrp-induced Bax expression in HepG2 cells. These results implicate that induction of autophagy plays a regulatory role in adiponectin-induced apoptosis of cancer cells, and thus inhibition of autophagy would be a novel promising target to enhance the efficiency of cancer cell apoptosis by adiponectin.

• BMB Reports
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• v.48 no.7
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• pp.401-406
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• 2015

Here we report that the H3K9 demethylase KDM3B represses transcription of the angiogenesis regulatory gene, ANGPT1. Negative regulation of ANGPT1 by KDM3B is independent of its Jumonji (JmjC) domain-mediated H3K9 demethylase activity. We demonstrate that KDM3B downregulates ANGPT1 via interaction with SMRT, and suggest that the repressor complex is formed at the promoter area of ANGPT1. Using MTT and wound healing assays, depletion of KDM3B was found to increase cell proliferation and cell motility, indicating that KDM3B has a role in angiogenesis. [BMB Reports 2015; 48(7): 401-406]

• BMB Reports
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• v.39 no.1
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• pp.97-104
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• 2006

Endostatin is a tumor-derived angiogenesis inhibitor, and the endogenous 20 kDa carboxyl-terminal fragment of collagen XVIII. In addition to inhibiting angiogenesis, endostatin inhibits tumor growth and the induction of apoptosis in several endothelial cell types. However, the mechanisms that regulate endostatin-induced apoptotic cell death are unclear. Here, we investigated apoptotic cell death and the underlying regulatory mechanisms elicited of endostatin in human umbilical vein endothelial cells (HUVECs). Endostatin was found to induce typical apoptotic features, such as, chromatin condensation and DNA fragmentation in these cells. Thus, as the phosphoinositide 3-OH kinase (PI3K)/protein kinase B (PKB) signaling pathway has been shown to prevent apoptosis in various cell types, we investigated whether this pathway could protect cells against endostatin induced apoptosis. It was found that the inhibition of PI3K/PKB significantly increased endostatin-induced apoptosis, and that endostatin-induced cell death is physiologically linked to PKB-mediated cell survival through caspase-8.