• Korean Journal of Microbiology
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• v.37 no.2
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• pp.145-150
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• 2001

Reactivation of human cytomegalovirus (HCMV) from latency is often fatal to immunocompromised individuals. To understand the effect of HCMV on human monocytes where HCMV establishes latency, two human monocyte cell lines at different stages in differentiation, THP-1 and HL-60 were infected with HCMV. While the viability and morphology of HL-60 cells were not significantly affected by HCMV, the viability of THP-1 cells was dramatically decreased by HCMV infection. THP-1 cells infected with HCMV became aggregated and adhered to the surface of culture dishes, probably due to the increased expression of adherence molecules CD11b on the infected THP-1 cells. THP-1 cells established a latent HCMV infection were induced to differentiate by treatment with TPA and hydrocortisone. Recovery of infectious HCMV from the culture supernatant of differentiated THP-1 cells was dependent on the time of induction of differentiation after HCMV infection. Thus, in vitro model of reactivation of HCMV from latently infected monocytes was established.

• Korean Journal of Pharmacognosy
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• v.43 no.2
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• pp.157-162
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• 2012

In order to investigate the immunostimulating effect of mycelia extract of Phellinus linteus (PLM) on human monocyte THP-1 and rat peritoneal macrophage cell, we examined measuring cytokine secretion (IL-6 and TNF-${\alpha}$). The production of IL-6 and TNF-a in human monocyte THP-1 was slight increased dose-dependently when the cells were challenged with PLM for 72 hrs. It was also observed that the treatment of PLM with LPS augmented the production of IL-6 and TNF-a in human monocyte THP-1. It was also observed that the treatment of PLM with LPS augmented the production of IL-6 and TNF-${\alpha}$ in human monocyte THP-1. The production of IL-6 and TNF-${\alpha}$ in rat peritoneal macrophage was significantly enhanced when the cells were treated PLM with LPS for 72 hrs. Moreover, the proliferation rate of rat spleen cells was increased in a dose dependent manner as the cells were treated with PLM and Concanavalin A.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.177-182
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• 2018

This study examined the effects of zerumbone on monocyte migration. Monocytes are recognized as important mediators of various inflammatory diseases, and the possibility of controlling inflammatory diseases by regulating the monocyte functions, such as activity and mobility, has been reported. MCP-1, which is a chemokine with levels that increase upon inflammation, causes the migration of the monocyte cell line, THP-1. Migration occurred at a concentration of 10 ng/mL MCP-1, and the highest migration occurred at 100 ng/mL and 200 ng/mL. MCP-1-induced THP-1 migration decreased by more than 40% in the presence of zerumbone. The concentration of cAMP, an important secondary messenger of the CCR2 signaling pathway, the MCP-1 receptor, was increased in the culture medium after a zerumbone treatment. The concentrations of cAMP decreased significantly under the MCP-1 treatment condition only. On the other hand, an increase in cAMP was observed when zerumbone and MCP-1 were treated simultaneously. Erk phosphorylation induced by an MCP-1 treatment was also found to decrease with the zerumbone treatment. This study introduces the possibility of controlling inflammatory diseases through the function of zerumbone, which regulates the migration of monocytes.

• Journal of Life Science
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• v.32 no.2
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• pp.142-147
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• 2022

Oxysterols are known to be involved in the physiopathology of atherosclerosis. Since 7-ketocholesterol (7-KC) is found in large amounts in oxysterols and in atherosclerotic plaque, the study on how 7-KC may affect monocyte differentiation induced by phorbol myristate acetate (PMA) in the monocytic cell line, THP-1, is essential. 7-KC induced a dose-dependent reduction in cell proliferation without inducing cytotoxicity, and the substantial staining of Nile red demonstrates the increased absorption of intracellular lipids. Although 7-KC itself did not increase cell adhesion, it markedly decreased the adhesion of cells treated with PMA. Furthermore, by observing the effect of 7-KC on phagocytosis using fluorescent-labeled latex beads, 7-KC's ability to abolish phagocytosis in PMA-stimulated macrophages was illustrated. The effect of 7-KC on the expression of selected protein markers on the process of differentiation induced by PMA in THP-1 cells was also examined. 7-KC inhibited expression of ICAM-1, CD11a, SR-A1, and SR-B2 (CD36) in PMA-stimulated THP-1 cells. Conversely, 7-KC drastically increased the expression of SR-D1 (CD68)in PMA-stimulated THP-1 cells. In conclusion, these results suggest that 7-KC modulates monocyte differentiation and activation via the intracellular accumulation of lipid droplets.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.333-350
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• 1999

The modulation of leukocyte cell surface adhesion molecules may influence the development of cellular events that determine the course of the inflammatory process. Direct interaction between activated T cells and monocytes resulted in a large production of $IL-1{\beta}$ by monocytes. In this reactions, adhesion molecules play an important part, yet the role of them in Tmonocytes interaction remain unclear. This study was undertaken in an effort to elucidate, 1) the influence of 1.25(OH)$_2D_3-induced$ differentiation on the monocyte responsiveness to direct contact with T lymphocytes, and 2) the role of adhesion molecules on the T-monocyte direct interaction. Initially, I observed that direct contact of monocyte cell line THP-1 with stimulated fixed T cell line HuT78 markedly induces IL-1${\beta}$ production by THP-1. $IL-1{\beta}$ production was higher when THP-1 had been previously exposed to 1.25(OH)$_2D_3$ as compared to control, with ${\alpha}$- 1.25(OH)$_2D_3$ dose-dependent and exposure time-dependent manner. It was shown that 1.25(OH)$_2D_3$ also increased the expression of ${\beta}_2$ integrin adhesion receptor Mac-1(CD11b/CD18) dose- and timedependently, but did not increase the expression of human leukocyte antigen- D(HLA-D) and intercellular adhesion molecule-1(ICAM-1). The $IL-1{\beta}$ producing activity of THP-1 cells correlated well with the ability to induce the Mac-1 expression on THP-1 surface. Monoclonal antibody raised against relevant cell surface glycoproteins on THP-1 were tested for their ability to block the response of THP-1 to T cells. Antibody to Mac-1 only partially blocked $IL-1{\beta}$ production by THP-1, whereas antibodies to ICAM-1 and HLA-D did not. These data indicate that regulation of Mac-1 expression on THP-1 cells can alter the responsiveness of these cells to contact by activated T cells, however other unknown structures on the THP-1 cells may be involved in this process also.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.285-290
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• 2007

The leukocyte recruitment and transmigration across the endothelial barrier into the vessel wall are crucial steps in atherosclerosis. Leukocyte trafficking on the endothelium is elicited by induction of endothelial adhesion molecules, and its transmigration is mediated by degradation of basement membrane proteins through enzymatic activity of matrix metalloproteinases (MMP). The current study investigated whether resveratrol, a polyphenol present in grapes and red wine, was capable of inhibiting leukocyte adhesion to tumor necrosis factor (TNF)-${\alpha}$-activated endothelium. It was found that resveratrol inhibited the TNF-${\alpha}$-activated endothelial expression of vascular cell adhesion molecule-1 in a dose-dependent manner. In addition, resveratrol hampered THP-1 monocyte adhesion to activated endothelial cells. This study further examined whether resveratrol interfered with transendothelial migration of leukocytes. The MMP-2 gelatinolytic activity of endothelial cells was enhanced by TNF-${\alpha}$, which was attenuated by an addition of ${\geq}25{\mu}M$ resveratrol. In addition, 25 ${\mu}M$ resveratrol mitigated the MMP-9 activity of THP-1 cells, followed by a marked inhibition of transendothelial migration. These results demonstrated that resveratrol suppressed monocyte adhesion and migration induced by TNF-${\alpha}$ through modulating expression of adhesion molecules and gelatinolytic activity of MMP. These findings suggest that dietary resveratrol may be therapeutic agent for inhibiting leukocyte recruitment into the subendothelium during inflammatory atherosclerosis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1305-1313
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• 2009

Saengjihwangeum-ja (SJHEJ) was recorded in DongEuiBoGam as being able to be used for treatment of Sogal whose concept had been applied to Diabetes Mellitus (DM). Modification of proteins by long term circulation of glucose leads to the formation of advanced glycation end product(AGE). Recent immunological studies demonstrated that ligation of AGE play an important role in the development of diabetic complications including atherosclerosis, which includes activation, adhesion, and migration of monocytes. Also, AGE and Maillard reaction product(MRP) could augment monocyte inflammatory responses via ligation of AGE receptor. In this study, the effects of SJHEJ extracts on the expression of inflammatory response-related genes such as tumor necrosis factor-$\alpha$, monocyte chemoattractant protein-1, interferon-g-inducible protein-10, and cyclooxygenase-2 in the human monocyte cell line, THP-1 cells. Reverse transcriptase-polymerase chain reaction revealed that SJHEJ had inhibitory effects on the expression of the TNF-a, MCP-1, IP-10, COX2, IL-1b genes in MRP-induced THP-1 cells. Treatment with SJHEJ had reduced reactive oxygen production in THP-1 cells stimulated by MRP. These inhibitory effects might be exerted via prevention of oxidative stress in activated monocytes. In addition, radical scavenging activity of SJHEJ was increased. These results suggest that SJHEJ has a beneficial effects for improve diabetic vascular complication.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.293-300
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• 2022

Lipoteichoic acid (LTA) regulates the immune system, including inflammatory responses, through TLR2-mediated signaling pathways. LTA isolated from Staphylococcus aureus (aLTA) has been shown to induce apoptosis, but the detailed mechanism has not been identified. We found that aLTA induced apoptosis through an autocrine mechanism in the human monocyte-like cell line, THP-1. We observed that the expression level of the anti-apoptosis protein, Bcl2, was suppressed in LTA-treated THP-1 cells. In addition, the cytokines, TNF-α and IFN-γ, which have been shown to induce apoptosis in some cell lines, were involved in THP-1 cell death via the modulation of Bcl2. The suppression of Bcl2 by aLTA was recovered when the negative regulator, SOCS-1, was knocked down. Taken together, these results showed that aLTA induced apoptosis in THP-1 cells through an autocrine mechanism of cytokines and SOCS-1-mediated Bcl2 inhibition.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.245-251
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• 2019

This study examined the effects of 2-methoxy-1,4-naphthoquinone (MQ) on the monocyte chemoattractant protein-1 (MCP-1)-induced migration of monocytes, which is an important phenomenon for the body defense and immune response. MQ is a major component extracted from Impatiens balsamina leaves, which have been used for many years in Asian medicine for the treatment of a range of diseases and pain. The cytotoxicity of MQ began to appear at a concentration of $10{\mu}M$, and approximately 50% cytotoxicity was confirmed at $100{\mu}M$. The MCP-1 induced migration of the THP-1 monocyte cell line increased after MQ treatment in a dose dependent manner and the largest increase was observed at $0.1{\mu}M$. The level of cAMP expression decreased after a treatment with $0.1{\mu}M$ MQ. The phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2), a key signaling protein involved in the signaling pathway of C-C motif chemokine receptor 2 (CCR2), a receptor for MCP-1, was increased by the simultaneous treatment of $0.1{\mu}M$ MQ. These results show that MQ increases the MCP-1-induced migration of THP-1, decreases the level of cAMP expression, and increases the level of Erk1/2 phosphorylation.

• Journal of Microbiology
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• v.40 no.3
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• pp.224-229
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• 2002

The effect of human cytomegalovirus (HCMV) on three human monocyte cell lines at different stages of differentiation was investigated. While the viability of HL-60 cells or U-937 cells was not significantly affected by HCMV infection, the viability of THP-1 cells was reduced. Acridine orange/ethidiurn bromide staining revealed that the reduction of THP-1 cell viability was due to increased apoptotic death following HCMV infection. Apoptosis in HL-60 cells was not affected by HCMV infection, and induction of apoptosis of U-937 cells by HCMV was intermediate between HL-60 and THP-1 cells. Since HL-60 cells are the least differentiated and THP-1 cells are the most differentiated, the induction of apoptosis of human monocytes appears to be related to the degree of cell differentiation. Flow cytometric and confocal microscopic studies using fluorescent calcium indicator Fluo-3 suggested a significant increase in intracellular free calcium concentration (［Ca$\^$2+/］i) in THP-1 cells undergoing apoptosis by HCMV infection. Again ［Ca$\^$2+/］i in HCMV-infected HL-60 cells was not critically altered, and that in HCMV-infected U-937 cells was intermediate between THP-1 cells and HL-60 cells. Calcium influx blockers such as verapamil and nifedipine partially reversed HCMV-induced apoptosis in THP-1 cells.