• The Korean Journal of Physiology and Pharmacology
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• 제21권3호
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• pp.301-308
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• 2017

27-Hydroxycholesterol induces differentiation of monocytic cells into mature dendritic cells, mDCs. In the current study we sought to determine roles of the PI3K and the ERK pathways in the 27OHChol-induced differentiation. Up-regulation of mDC-specific markers like CD80, CD83 and CD88 induced by stimulation with 27OHChol was significantly reduced in the presence of LY294002, an inhibitor of PI3K, and U0126, an inhibitor of ERK. Surface expression of MHC class I and II molecules elevated by 27OHChol was decreased to basal levels in the presence of the inhibitors. Treatment with LY294002 or U0126 resulted in recovery of endocytic activity which was reduced by 27OHChol. CD197 expression and cell adherence enhanced by 27OHChol were attenuated in the presence of the inhibitors. Transcription and surface expression of CD molecules involved in atherosclerosis such as CD105, CD137 and CD166 were also significantly decreased by treatment with LY294002 and U0126. These results mean that the PI3K and the ERK signaling pathways are necessary for differentiation of monocytic cells into mDCs and involved in over-expression of atherosclerosis-associated molecules in response to 27OHChol.

• The Korean Journal of Physiology and Pharmacology
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• 제18권6호
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• pp.475-480
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• 2014

We investigated the question of whether cholesterol catabolite can influence expression of inflammatory cytokines via Toll-like receptors (TLR) in monocytic cells. Treatment of THP-1 monocytic cells with 27-hydroxycholesterol (27OHChol) resulted in induction of gene transcription of TLR6 and elevated level of cell surface TLR6. Addition of FSL-1, a TLR6 agonist, to 27OHChol-treated cells resulted in transcription of the $IL-1{\alpha}$ gene and enhanced secretion of the corresponding gene product. However, cholesterol did not affect TLR6 expression, and addition of FSL-1 to cholesterol-treated cells did not induce expression of $IL-1{\alpha}$. Using pharmacological inhibitors, we investigated molecular mechanisms underlying the expression of TLR6 and $IL-1{\alpha}$. Treatment with Akt inhibitor IV or U0126 resulted in significantly attenuated expression of TLR6 and $IL-1{\alpha}$ induced by 27OHChol and 27OHChol plus FSL-1, respectively. In addition, treatment with LY294002, SB202190, or SP600125 resulted in significantly attenuated secretion of $IL-1{\alpha}$. These results indicate that 27OHChol can induce inflammation by augmentation of TLR6-mediated production of $IL-1{\alpha}$ in monocytic cells via multiple signaling pathways.

• IMMUNE NETWORK
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• 제23권5호
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• pp.40.1-40.14
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• 2023

Glucocorticoids suppress the vascular inflammation that occurs under hypercholesterolemia, as demonstrated in an animal model fed a high-cholesterol diet. However, the molecular mechanisms underlying these beneficial effects remain poorly understood. Because cholesterol is oxidized to form cholesterol oxides (oxysterols) that are capable of inducing inflammation, we investigated whether glucocorticoids affect the immune responses evoked by 7α-hydroxycholesterol (7αOHChol). The treatment of human THP-1 monocytic cells with dexamethasone (Dex) and prednisolone (Pdn) downregulated the expression of pattern recognition receptors (PRRs), such as TLR6 and CD14, and diminished 7αOHChol-enhanced response to FSL-1, a TLR2/6 ligand, and lipopolysaccharide, which interacts with CD14 to initiate immune responses, as determined by the reduced secretion of IL-23 and CCL2, respectively. Glucocorticoids weakened the 7αOHChol-induced production of CCL2 and CCR5 ligands, which was accompanied by decreased migration of monocytic cells and CCR5-expressing Jurkat T cells. Treatment with Dex or Pdn also reduced the phosphorylation of the Akt-1 Src, ERK1/2, and p65 subunits. These results indicate that both Dex and Pdn impair the expression of PRRs and their downstream products, chemokine production, and phosphorylation of signaling molecules. Collectively, glucocorticoids suppress the innate immune response and activation of monocytic cells to an inflammatory phenotype enhanced or induced by 7αOHChol, which may contribute to the anti-inflammatory effects in hypercholesterolemic conditions.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.168.1-168.1
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• 2001

• Journal of Periodontal and Implant Science
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• 제39권2호
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• pp.177-184
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• 2009

Purpose: Interleukin-8 (IL-8) is an important mediator of immune and inflammatory reactions and is produced by a variety of different cell types. This study was undertaken to investigate the effects of lipopolysaccharides (LPSs) from Prevotella intermedia and Prevotella nigrescens, the major causes of inflammatory periodontal disease, on the production of IL-8 and the expression of IL-8 mRNA in differentiated THP-1 cells, a human monocytic cell line. Methods: LPSs from P. intermedia ATCC 25611 and P. nigrescens ATCC 33563 were prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. Results: We found that LPS preparations from P. intermedia and P. nigrescens can induce IL-8 mRNA expression and stimulate the release of IL-8 in differentiated THP-1 cells without additional stimuli. Conclusions: There are no previous reports of the ability of P. intermedia and P. nigrescens LPS to stimulate the release of IL-8, and the present study clearly shows, for the first time, that LPSs from P. intermedia and P. nigrescens fully induced IL-8 mRNA expression and IL-8 production in differentiated human monocytic cell line THP-1. The ability of P. intermedia and P. nigrescens LPS to promote the production of IL-8 may be important in the pathogenesis of inflammatory periodontal disease.

• BMB Reports
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• 제33권5호
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• pp.402-406
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• 2000

In order to understand the role of AGP on the differentiation of promyelocytic leukemia cells, the AGP expression and its relation to cytokines were investigated during granulocytic or monocytic differentiation of HL-60 cells. When HL-60 cells were treated with all-trans-retinoic acid (ATRA) for 5 days, the cells were fully differentiated into granulocytes, and the AGP mRNA and protein levels were continuously increased up to 5 days in a dose- and time- dependent manner. However, in the case of the monocytic differentiation of HL-60 cells by tetradeanoyl phorbol acetate (TPA), the AGP gene expression was not induced. In addition, $IL-1{\alpha}$, $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ mRNAs were also enhanced during granulocytic differentiation. These cytokine transcripts showed a peak level 3 days after the ATRA treatment. It decreased gradually thereafter. However, direct addition of recombinant cytokines ($IL-1{\beta}$, IL-6 and $TNF-{\alpha}$) and dexamethasone to the HL-60 cell cultures showed no AGP induction. These findings suggest that the AGP and proinflammatory cytokines are expressed in ATRA-treated promyelocytic cells. However, these cytokines do not act as autocrine inducers on AGP expression. This fact implies that the AGP expression during granulocytic differentiation of HL-60 cells is induced through a signal pathway different from hepatocyte signaling in inflammation.

• 대한의생명과학회지
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• 제15권1호
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• pp.93-96
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• 2009

House dust mites (HDMs) play an important role in the occurrence of allergic diseases such as asthma and atopic dermatitis. Dermatophagoides pteronyssinus (Der p) is one of the most prevalent HDMs. It mediates the activation of T cells and monocytes, and induces the elevation of immunoglobulin E levels in allergic diseases. However, the effects of Der p on human monocytes have not been fully understood. In the present study, we investigated whether or not Der p has a great effect on the chemotactic activity of the human monocytic cell line, THP-1 cells, as induced by CC chemokines. We also show that the Der p extract (DpE) increased the chemotactic activity of THP-1 cells in response to MCP-1, RANTES, MIP-1${\alpha}$, and TARC, but had no effect on the expressions of CC chemokine receptors (CCRs) binding to CC chemokines in THP-1 cells. Protease inhibitors, such as aprotinin and E64, blocked the increased chemotaxis, while cytoplasmic $Ca^{2+}$ influx mediated by these chemokines was inhibited by DpE. These results indicate that DpE increases the chemotactic activity of THP-1 cells in response to CC chemokines by regulating the cells' protease-dependent mechanism. This finding may be useful in identifying the pathogenesis of allergic diseases induced by Der p.

• Molecules and Cells
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• 제43권9호
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• pp.793-803
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• 2020

Myeloid-derived suppressor cells (MDSCs) promote tumour progression by contributing to angiogenesis, immunosuppression, and immunotherapy resistance. Although recent studies have shown that microRNAs (miRNAs) can promote the expansion of MDSCs in the tumour environment, the mechanisms involved in this process are largely unknown. Here, we report that microRNA 449c (miR-449c) expression was upregulated in myeloid progenitor cells upon activation of C-X-C motif chemokine receptor 2 (CXCR2) under tumour conditions. MiR-449c upregulation increased the generation of monocytic MDSCs (mo-MDSCs). The increased expression of miR-449c could target STAT6 mRNA in myeloid progenitor cells to shift the differentiation balance of myeloid progenitor cells and lead to an enhancement of the mo-MDSCs population in the tumour environment. Thus, our results demonstrate that the miR-449c/STAT6 axis is involved in the expansion of mo-MDSCs from myeloid progenitor cells upon activation of CXCR2, and thus, inhibition of miR-449c/STAT6 signalling may help to attenuate tumour progression.

• Nutrition Research and Practice
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• 제2권2호
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• pp.134-137
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• 2008

Atherosclerosis is characterized by a chronic inflammatory disease, and chemokines play an important role in both initiation and progression of atherosclerosis development. Leukotactin-1 (Lkn-1/CCLl5), a new member of the human CC chemokine family, is a potent chemoattractant for leukocytes. Our previous study has demonstrated that Lkn-1/CCL15 plays a role in the initiation of atherosclerosis, however, little is currently known whether Lkn-1/CCL15 is associated with the progression of atherosclerosis. Matrix metalloproteinases (MMPs) in human coronary atherosclerotic lesions playa crucial role in the progression of atherosclerosis by altering the vulnerability of plaque rupture. In the present study, we examined whether Lkn-1/CCLl5 modulates MMP-9 release, which is a prevalent form expressed by activated macrophages and foam cells. Human THP-1 monocytic cells and/or human peripheral blood monocytes (PBMC) were treated with phorbol myristate acetate to induce their differentiation into macrophages. Foam cells were prepared by the treatment of THP-1 macrophages with human oxidized LDL. The macrophages and foam cells were treated with Lkn-1/CCL15, and the levels of MMP-9 release were measured by Gelatin Zymography. Lkn-1/CCL15 significantly enhanced the levels of MMP-9 protein secretion from THP-1 monocytic cells-derived macrophages, human PBMC-derived macrophages, as well as macrophage-derived foam cell in a dose dependent manner. Our data suggest that the action of Lkn-1/CCL15 on macrophages and foam cells to release MMP-9 may contribute to plaque destabilization in the progression of atherosclerosis.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.115-115
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• 1998

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