• Advances in Traditional Medicine
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• 제5권3호
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• pp.216-230
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• 2005

Although the field of study in immune enhancing compounds is relatively new, natural products from plants represent a rich and promising source of novel molecules with immunomodulating properties, Microglial cells, the main immune effector cells of the brain, usually display a ramified morphology and low expression levels of immunologically relevant antigens such as MHC class I and class II. Since any compound which participates in activation of phagocytic cells contributes to the production of potentially toxic factors, the search for convenient in vitro test-systems and study of mechanisms of action of these agents are of great interest. Human blood polymorphonuclear (PMN) cells and primary microglial cells isolated from Sprague-Dawley rats were used as cellular screening tests for study of phagocytosis-stimulating action of immunomodulating agents. Numbers of phagocytic activity were evaluated by the phagocyte ingestion of yeast cells and NO-synthase activity, nitrite production, and nitroblue tetrazolium test were determined after phagocyte stimulation. It was possible to demonstrate that indexes of phagocytic activity can be used as quantitative indicators for measurement immunomodulating activity. As a positive control, Zymosan A-induced phagocytosis in both PMN cells and primary microglial cells was used. $IFN-{\gamma}$ (0.1 -1 U/ml) stimulated phagocytosis in PMN cells 1.2 times after 2 - 3 h incubation, although at higher concentrations (10 - 100 U/ml) it strongly inhibited phagocytosis. In a similar way, at higher concentrations, $IFN-{\gamma}$ (100 - 500 U/ml) suppressed phagocytosis in zymosan-A stimulated microglial cells. When Polypodium leucotomus, cambricum and vulgare extracts were tested alone, increased levels of phagocytosis were observed in PMN. In addition, microglial cells showed both increased phagocytosis and MHC class-II antigen expressions. Surprisingly, when PMN and microglia were treated with a combination of Polypodium and $IFN-{\gamma}$, phagocytosis was not inhibited. We did not find changes in NO-synthase activity and nitrite production in both microglia and PMN cells activated by different immunomodulating agents. These results indicate that primary microglial cell cultures as well as human PMN cells can provide reproducible quantitative results in screening phagocytic activity of different immunoactive compounds. Furthermore, both inhibitory or activation mechanisms might be studied using these in vitro experimental approaches.

• 대한의생명과학회지
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• 제24권4호
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• pp.305-310
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• 2018

Microglia are emerging as critical regulators of innate immune responses in AD and other neurodegenerative disorders, highlighting the importance of understanding their molecular and cellular mechanisms. We attempted to determine the role of crosstalk signaling between $IFN-{\gamma}$ and $TGF-{\beta}$ in $A{\beta}$ clearance by microglia cells. We used in vitro and in vivo mouse models that recapitulated acute and chronic aspects of microglial responses to $A{\beta}$ peptides. We showed that crosstalk signaling between $TGF-{\beta}$ and Smad2 was an important mediator of neuro-inflammation. These findings suggest that microglial $TGF-{\beta}$ activity enhances the pathological progression to AD. As $TGF-{\beta}$ displays broad regulatory effects on beneficial microglial functions, the activation of inflammatory crosstalk signaling between $TGF-{\beta}$ and Smad2 may be a promising strategy to restore microglial functions, halt the progression of $A{\beta}$-driven pathology, and prevent AD development.

• Toxicological Research
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• 제28권1호
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• pp.5-9
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• 2012

It has been shown that the accumulation of prion in the cytoplasm can result in neurodegenerative disorders. Synthetic prion peptide 106-126 (PrP) is a glycoprotein that is expressed predominantly by neurons and other cells, including glial cells. Prion-induced chronic neurodegeneration has a substantial inflammatory component, and an increase in the levels of matrix metalloproteinases (MMPs) may play an important role in neurodegenerative development and progression. However, the expression of MMPs in PrP induced rat astrocytes and microglia has not yet been compared. Thus, in this study, we examined the fluorescence intensity of CD11b positive microglia and Glial Fibrillary Acidic Protein (GFAP) positive astrocytes and found that the fluorescent intensity was increased following incubation with PrP at 24 hours in a dose-dependent manner. We also observed an increase in interleukin-1 beta (IL-$1{\beta}$) and tumor necrosis factor alpha (TNF-${\alpha}$) protein expression, which are initial inflammatory cytokines, in both PrP induced astrocytes and microglia. Furthermore, an increase MMP-1, 3 and 11 expressions in PrP induced astrocytes and microglia was observed by real time PCR. Our results demonstrated PrP induced activation of astrocytes and microglia respectively, which resulted in an increase in inflammatory cytokines and MMPs expression. These results provide the insight into the different sensitivities of glial cells to PrP.

• 대한의생명과학회지
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• 제23권4호
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• pp.411-415
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• 2017

To evaluate the protective effects of Plantago Major extract (PME) in stimulated BV-2 microglial cells and its anti-oxidant properties, cell viability assessment was performed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Lipopolysaccharide (LPS) was used to activate BV-2 microglia. Nitric oxide (NO) levels were measured using Griess assay. Tumor necrosis factor-alpha (TNF-${\alpha}$) production was evaluated by enzyme-linked immunosorbent assay (ELISA). Antioxidant properties were evaluated by 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. LPS-activated excessive release of NO in BV-2 cells was significantly inhibited by PME (P < 0.001 at $100{\mu}g/mL$). PME also scavenged DPPH radicals in a dose-dependent manner (P < 0.05 at $10{\mu}g/mL$ and P < 0.001 at $20{\sim}200{\mu}g/mL$). These results indicate that PME attenuated neuroinflammatory responses in LPS-activated BV-2 microglia by inhibiting excessive production of pro-inflammatory mediators such as NO and TNF-${\alpha}$. The anti-neuroinflammatory potential of PME may be related to its strong antioxidant properties.

• International Journal of Oral Biology
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• 제45권4호
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• pp.225-231
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• 2020

Glial cells, including astrocytes and microglia, interact closely with neurons and modulate pain transmission, particularly under pathological conditions. In this study, we examined the excitability of substantia gelatinosa (SG) neurons of the spinal dorsal horn using a patch clamp recording to investigate the roles of microglial activation in the nociceptive processes of rats. We used xanthine/xanthine oxidase (X/XO), a generator of superoxide anion (O2·-), to induce a pathological pain condition. X/XO treatment induced an inward current and membrane depolarization. The inward current was significantly inhibited by minocycline, a microglial inhibitor, and fluorocitrate, an astrocyte inhibitor. To examine whether toll-like receptor 4 (TLR4) in microglia was involved in the inward current, we used lipopolysaccharide (LPS), a highly specific TLR4 agonist. The LPS induced inward current, which was decreased by pretreatment with Tak-242, a TLR4-specific inhibitor, and phenyl N-t-butylnitrone, a reactive oxygen species scavenger. The X/XO-induced inward current was also inhibited by pretreatment with Tak-242. These results indicate that the X/XO-induced inward current of SG neurons occurs through activation of TLR4 in microglial cells, suggesting that neuroglial cells modulate the nociceptive process through central sensitization.

• 생물정신의학
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• 제22권2호
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• pp.29-33
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• 2015

The brain maintains homeostasis and normal microenvironment through dynamic interactions of neurons and neuroglial cells to perform the proper information processing and normal cognitive functions. Recent post-mortem investigations and animal model studies demonstrated that the various brain areas such as cerebral cortex, hippocampus and amygdala have abnormalities in neuroglial numbers and functions in subjects with mental illnesses including schizophrenia, dementia and mood disorders like major depression and bipolar disorder. These findings highlight the putative role and involvement of neuroglial cells in mental disorders. Herein I discuss the physiological roles of neuroglial cells such as astrocytes, oligodendrocytes, and microglia in maintaining normal brain functions and their abnormalities in relation to mental disorders. Finally, all these findings could serve as a useful starting point for potential therapeutic concept and drug development to cure unnatural behaviors and abnormal cognitive functions observed in mental disorders.

• 대한본초학회지
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• 제37권5호
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• pp.83-88
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• 2022

Objectives : Jakyakgamcho-tang (JGT) has been traditionally used to treat muscular convulsion and pain in South Korea. According to recent studies, JGT has been reported to have anti-depression, anti-inflammation, anti-oxidative, anti-diabetics, anti-spasm and analgesic effects, but studies on its anti-neuroinflammatory and neuroprotective effect have not been deeply conducted. Thus, we investigated the anti-neuroinflammatory activity of JGT on lipopolysaccharide (LPS)-stimulated mouse microglia cells. Methods : To investigate the anti-neuroinflammatory effects of JGT on BV2 microglial cells, we examined the production of nitric oxide (NO) using griess assay, and mRNA expressions of pro-inflammatory cytokines such as interleukin (IL)-1𝛽, IL-6, and tumor necrosis factor (TNF)-𝛼 using real time RT-PCR. Furthermore, to determine the regulating mechanisms of JGT, we investigated the heme oxygenase (HO)-1 by real time RT-PCR. Results : Pre-treatment of JGT effectively decreased NO production in LPS-stimulated BV2 cells at concentrations without cytotoxicity. Additionally, JGT significantly suppressed the production of IL-1𝛽, IL-6, and TNF-𝛼 in LPS-stimulated BV2 cells. Furthermore, JGT activated the HO-1 expression, which is one of the immunomodulatory signaling molecules. And the abolishment of HO-1 by tin protoporphyrin IX (SnPP, the HO-1 inhibitor) reversed the anti- inflammatory activity of JGT in LPS-stimulated BV2 cells. Conclusions : Our results suggest that the JGT has anti-neuroinflammatory effect through the activation of HO-1 in LPS-stimulated BV2 cells. Thereby, JGT could expected to be used for the prevention and treatment of neurodegenerative disease related to neuroinflammation.

• 대한한의학회지
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• 제43권4호
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• pp.20-32
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• 2022

Objectives: Kyungok-go (KOG) is a traditional multi-herbal medicine commonly used for enforcing weakened immunity for long time. Recently, there are several reports that KOG has anti-inflammatory and immuno-stimulatory activities in many experimental models. However, the protective effects of KOG on neuronal inflammation are still undiscovered. Thus, we investigated the neuro-protective activity of KOG on lipopolysaccharide (LPS)-stimulated mouse microglia cells. To find out KOG's anti-neuroinflammatory effects on microglial cells, we examined the production of nitrite using griess assay, and mRNA expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α using real time RT-PCR. In addition, to examine the regulating mechanisms of KOG, we investigated the protein expression of mitogen-activated protein kinases (MAPKs) and Iκ-Bα by western blot. KOG inhibited the elevation of nitrite, iNOS and COX-2 on LPS-stimulated BV2 cells. Also, KOG significantly inhibited the pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α on LPS-stimulated BV2 microglial cells. Moreover, KOG inhibited the activation of c-Jun N-terminal kinase (JNK), P38 and degradation of Iκ-Bα but not the activation of extracellular signal regulated kinase (ERK) on LPS-stimulated BV2 microglial cells. These results showed KOG has the anti-inflammatory effects through the inhibition on nitrite, iNOS, COX-2, IL-1β, IL-6, and TNF-α via the deactivation of JNK, p38 and nuclear factor (NF)-κB on LPS-stimulated BV2 microglial cells. Thereby, KOG could offer the new and promising treatment for neurodegenerative disease related to neuroinflammation.

• Archives of Pharmacal Research
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• 제27권9호
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• pp.954-960
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• 2004

Expression of the NF-$textsc{k}$B-dependent genes responsible for inflammation, such as TNF-$\alpha$, IL-1$\beta$, and nitric oxide synthase (NOS), contributes to chronic inflammation which is a major cause of neurodegenerative diseases (i.e. Alzheimer＇s disease). Although NF-$textsc{k}$B plays a biphasic role in different cells like neurons and microglia, controlling the activation of NF-$textsc{k}$B is important for its negative feedback in either activation or inactivation. In this study, we found that ursodeoxycholic acid (UDCA) inhibited I$textsc{k}$B$\alpha$ degradation to block expression of the NF-$textsc{k}$B-dependent genes in microglia when activated by $\beta$-amyloid peptide (A$\beta$). We also showed that when microglia is activated by $A\beta$42, the expression of A20 is suppressed. These findings place A20 in the category of ' protective ' genes, protecting cells from pro-inflammatory reper-toires induced in response to inflammatory stimuli in activated microglia via NF-$textsc{k}$B activation. In light of the gene and proteins for NF-$textsc{k}$B-dependent gene and inactivator for NF-$textsc{k}$B (I$textsc{k}$B$\alpha$), the observations now reported suggest that UDCA plays a role in supporting the attenuation of the production of pro-inflammatory cytokines and NO via inactivation of NF-$textsc{k}$B. Moreover, an NF-$textsc{k}$B inhibitor such as A20 can collaborate and at least enhance the anti-inflammatory effect in microglia, thus giving a potent benefit for the treatment of neurodegenerative diseases such as AD.uch as AD.

• Biomolecules & Therapeutics
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• 제26권2호
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• pp.210-217
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• 2018

Neuroinflammation is an immune response within the central nervous system against various proinflammatory stimuli. Abnormal activation of this response contributes to neurodegenerative diseases such as Parkinson disease, Alzheimer's disease, and Huntington disease. Therefore, pharmacologic modulation of abnormal neuroinflammation is thought to be a promising approach to amelioration of neurodegenerative diseases. In this study, we evaluated the synthetic flavone derivative 3',4'-dihydroxyflavone, investigating its anti-neuroinflammatory activity in BV2 microglial cells and in a mouse model. In BV2 microglial cells, 3',4'-dihydroxyflavone successfully inhibited production of chemokines such as nitric oxide and prostaglandin $E_2$ and proinflammatory cytokines such as tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 in BV2 microglia. It also inhibited phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor $(NF)-{\kappa}B$ activation. This indicates that the anti-inflammatory activities of 3',4'-dihydroxyflavone might be related to suppression of the proinflammatory MAPK and $NF-{\kappa}B$ signaling pathways. Similar anti-neuroinflammatory activities of the compound were observed in the mouse model. These findings suggest that 3',4'-dihydroxyflavone is a potential drug candidate for the treatment of microglia-related neuroinflammatory diseases.