• Biomolecules & Therapeutics
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• 제30권1호
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• pp.48-54
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• 2022

GPR43 (also known as FFAR2), a metabolite-sensing G-protein-coupled receptor stimulated by short-chain fatty acid (SCFA) ligands is involved in innate immunity and metabolism. GPR43 couples with Gα_i/o and Gα_q/11 heterotrimeric proteins and is capable of decreasing cyclic AMP and inducing Ca²⁺ flux. The GPR43 receptor has additionally been shown to bind β-arrestin 2 and inhibit inflammatory pathways, such as NF-κB. However, GPR43 shares the same ligands as GPR41, including acetate, propionate, and butyrate, and determination of its precise functions in association with endogenous ligands, such as SCFAs alone, therefore remains a considerable challenge. In this study, we generated novel synthetic agonists that display allosteric modulatory effects on GPR43 and downregulate NF-κB activity. In particular, the potency of compound 187 was significantly superior to that of pre-existing compounds in vitro. However, in the colitis model in vivo, compound 110 induced more potent attenuation of inflammation. These novel allosteric agonists of GPR43 clearly display anti-inflammatory potential, supporting their clinical utility as therapeutic drugs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권6호
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• pp.481-489
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• 2010

Introduction: TLR-5, a member of the toll-like receptor (TLR) family, is a element of the type I transmembrane receptors, which are characterized by an intracellular signaling domain homolog to the interleukin-1 receptor. These receptors recognize microbial components, particularly bacterial flagellin. All-trans retinoic acid (atRA, tretinoin), a natural metabolite of vitamin A, acts as a growth and differentiation factor in many tissues, and is also needed for immune functions. In this study, THP-1 human macrophage-monocytes were used to examine the mechanisms by which atRA regulated the expression of TLR-5. Because the molecular mechanism underlying this regulation at the transcriptional level is also unclear, this study examined which putative transcription factors are responsible for TLR-5 expression by atRA in immune cells. Materials and Methods: This study examined whether atRA induces the expression of TLR-5 in THP-1 cells using reverse transcription-polymerase chain reaction (RT-PCR), and which transcription factors are involved in regulating the TLR-5 promoter in RAW264.7 cells using a reporter assay system. Western blot analysis was used to determine which signal pathway is involved in the expression of TLR-5 in atRA-treated THP-1 cells. Results: atRA at a concentration of 10 nM greatly induced the expression of TLR-5 in THP-1 cells. Human TLR-5 promoter contains three Sp-1/GC binding sites around -50 bp and two NF-kB binding sites at -380 bp and -160 bp from the transcriptional start site of the TLR-5 gene. Sp-1/GC is primarily responsible for the constitutive TLR-5 expression, and may also contribute to NF-kB at -160 bp to induce TLR-5 after atRA stimulation in THP-1 cells. The role of NF-kB in TLR-5 expression was further confirmed by inhibitor pyrrolidine dithiocarbamate (PDTC) experiments, which greatly reduced the TLR-5 transcription by 70-80%. Conclusion: atRA induces the expression of the human TLR-5 gene and NF-kB is a critical transcription factor for the atRA-induced expression of TLR-5. Accordingly, it is conceivable that retinoids are required for adequate innate and adaptive immune responses to agents of infectious diseases. atRA and various synthetic retinoids have been used therapeutically in human diseases, such as leukemia and other cancers due to the antiproliferative and apoptosis inducing effects of retinoids. Therefore, understanding the molecular regulatory mechanism of TLR-5 may assist in the design of alternative strategies for the treatment of infectious diseases, leukemia and cancers.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.85-92
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• 2020

One of the omega-3 essential fatty acids, docosahexaenoic acid (DHA), is a significant constituent of the cell membrane and the precursor of several potent lipid mediators. These mediators are considered to be important in preventing or treating several diseases. Resolvin D5, an oxidized lipid mediator derived from DHA, has been known to exert anti-inflammatory effects. However, the detailed mechanism underlying these effects has not yet been elucidated in human monocytic THP-1 cells. In the present study, we investigated the effects of resolvin D5 on inflammation-related signaling pathways, including the extracellular signal-regulated kinase (ERK)-nuclear factor (NF)-κB signaling pathway. Resolvin D5 downregulated the production of interleukin (IL)-6 and chemokine (C-C motif) ligand 5 (CCL5). Additionally, these inhibitory effects were found to be modulated by mitogen-activated protein kinase (MAPK) and NF-κB in lipopolysaccharide (LPS)-treated THP-1 cells. Resolvin D5 inhibited the LPS-stimulated phosphorylation of ERK and translocation of p65 and p50 into the nucleus, resulting in the inhibition of IL-6 and CCL5 production. These results revealed that resolvin D5 exerts anti-inflammatory effects in LPS-treated THP-1 cells by regulating the phosphorylation of ERK and nuclear translocation of NF-κB.

• Nutrition Research and Practice
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• 제16권6호
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• pp.685-699
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• 2022

BACKGROUND/OBJECTIVES: Platycodon grandiflorum (PG) has long been known as a medicinal herb effective in various diseases, including bronchitis and asthma, but is still more widely used for food. Fermentation methods are being applied to increase the pharmacological composition of PG extracts and commercialize them with high added value. This study examines the hydrolyzed and fermented PG extract (HFPGE) fermented with Lactobacillus casei in RAW 264.7 cells, and investigates the effect of amplifying the immune and the probable molecular mechanism. MATERIALS/METHODS: HFPGE's total phenolic, flavonoid, saponin, and platycodin D contents were analyzed by colorimetric analysis or high-performance liquid chromatography. Cell viability was measured by the MTT assay. Phagocytic activity was analyzed by a phagocytosis assay kit, nitric oxide (NO) production by a Griess reagent system, and cytokines by enzyme-linked immunosorbent assay kits. The mRNA expressions of inducible nitric oxide synthase (iNOS) and cytokines were analyzed by reverse transcription-polymerase chain reaction, whereas MAPK and nuclear factor (NF)-κB activation were analyzed by Western blots. RESULTS: Compared to PGE, HFPGE was determined to contain 13.76 times and 6.69 times higher contents of crude saponin and platycodin D, respectively. HFPGE promoted cell proliferation and phagocytosis in RAW 264.7 cells and regulated the NO production and iNOS expression. Treatment with HFPGE also resulted in increased production of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, C-X-C motif chemokine ligand10, granulocyte-colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-1, and the mRNA expressions of these cytokines. HFPGE also resulted in significantly increasing the phosphorylation of NF-κB p65, extracellular signal-regulated kinase, and c-Jun N-terminal kinase. CONCLUSIONS: Taken together, our results imply that fermentation and hydrolysis result in the extraction of more active ingredients of PG. Furthermore, we determined that HFPGE exerts immunostimulatory activity via the MAPK and NF-κB signaling pathways.

• BMB Reports
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• 제56권6호
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• pp.359-364
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• 2023

KAI1/CD82, a membrane tetraspanin protein, can prevent various cancers and retinal disorders through its anti-angiogenic and anti-metastatic capacity. However, little is known about its anti-inflammatory effect and molecular mechanism. Therefore, the present study aimed to inLPSvestigate effect of a recombinant protein of the large extracellular domain of human KAI1 (Gly 111-Leu 228, rhKAI1) on lipopolysaccharides (LPS)-stimulated RAW264.7 macrophage-like cells and mouse bone marrow-derived macrophages (BMDM) and to identify its underlying mechanism. Our data showed that rhKAI1 suppressed expression levels of classically macrophages (M1) phenotype-related surface markers F4/80+CD86+ in LPS-stimulated BMDM and RAW264.7 cells. In addition, LPS markedly increased mRNA expression and release levels of pro-inflammatory cytokines and mediators such as interleukin (IL)-1β, IL-6, tumor necrosis factor-α, cyclooxygenase-2, nitric oxide and prostaglandin E2, whereas these increases were substantially down-regulated by rhKAI1. Furthermore, LPS strongly increased expression of NF-κB p65 in the nuclei and phosphorylation of ERK, JNK, and p38 MAPK. However, nuclear translocation of NF-κB p65 and phosphorylation of JNK were greatly reversed in the presence of rhKAI1. Especially, rhKAI1 markedly suppressed expression of toll-like receptor (TLR4) and prevented binding of LPS with TLR4 through molecular docking predict analysis. Importantly, Glu 214 of rhKAI1 residue strongly interacted with Lys 360 of TLR4 residue, with a binding distance of 2.9 Å. Taken together, these findings suggest that rhKAI1 has an anti-inflammatory effect on LPS-polarized macrophages by interacting with TLR4 and down-regulating the JNK/NF-κB signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제27권2호
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• pp.143-155
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• 2023

Percutaneous coronary intervention and acute coronary syndrome are both closely tied to the frequently occurring complication of coronary microembolization (CME). Resveratrol (RES) has been shown to have a substantial cardioprotective influence in a variety of cardiac diseases, though its function and potential mechanistic involvement in CME are still unclear. The forty Sprague-Dawley rats were divided into four groups randomly: CME, CME + RES (25 mg/kg), CME + RES (50 mg/kg), and sham (10 rats per group). The CME model was developed. Echocardiography, levels of myocardial injury markers in the serum, and histopathology of the myocardium were used to assess the function of the cardiac muscle. For the detection of the signaling of TLR4/MyD88/NF-κB along with the expression of pyroptosis-related molecules, ELISA, qRT-PCR, immunofluorescence, and Western blotting were used, among other techniques. The findings revealed that myocardial injury and pyroptosis occurred in the myocardium following CME, with a decreased function of cardiac, increased levels of serum myocardial injury markers, increased area of microinfarct, as well as a rise in the expression levels of pyroptosis-related molecules. In addition to this, pretreatment with resveratrol reduced the severity of myocardial injury after CME by improving cardiac dysfunction, decreasing serum myocardial injury markers, decreasing microinfarct area, and decreasing cardiomyocyte pyroptosis, primarily by blocking the signaling of TLR4/MyD88/NF-κB and also reducing the NLRP3 inflammasome activation. Resveratrol may be able to alleviate CME-induced myocardial pyroptosis and cardiac dysfunction by impeding the activation of NLRP3 inflammasome and the signaling pathway of TLR4/MyD88/NF-κB.

• Biomolecules & Therapeutics
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• 제23권6호
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• pp.531-538
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• 2015

Preceding infection or inflammation such as bacterial meningitis has been associated with poor outcomes after stroke. Previously, we reported that intracorpus callosum microinjection of lipopolysaccharides (LPS) strongly accelerated the ischemia/reperfusionevoked brain tissue damage via recruiting inflammatory cells into the ischemic lesion. Simvastatin, 3-hydroxy-3-methylgultaryl (HMG)-CoA reductase inhibitor, has been shown to reduce inflammatory responses in vascular diseases. Thus, we investigated whether simvastatin could reduce the LPS-accelerated ischemic injury. Simvastatin (20 mg/kg) was orally administered to rats prior to cerebral ischemic insults (4 times at 72, 48, 25, and 1-h pre-ischemia). LPS was microinjected into rat corpus callosum 1 day before the ischemic injury. Treatment of simvastatin reduced the LPS-accelerated infarct size by 73%, and decreased the ischemia/reperfusion-induced expressions of pro-inflammatory mediators such as iNOS, COX-2 and IL-$1{\beta}$ in LPS-injected rat brains. However, simvastatin did not reduce the infiltration of microglial/macrophageal cells into the LPS-pretreated brain lesion. In vitro migration assay also showed that simvastatin did not inhibit the monocyte chemoattractant protein-1-evoked migration of microglial/macrophageal cells. Instead, simvastatin inhibited the nuclear translocation of NF-${\kappa}B$, a key signaling event in expressions of various proinflammatory mediators, by decreasing the degradation of $I{\kappa}B$. The present results indicate that simvastatin may be beneficial particularly to the accelerated cerebral ischemic injury under inflammatory or infectious conditions.

• 대한수의학회지
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• 제57권2호
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• pp.97-104
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• 2017

Solanum lycopersicum, commonly known as tomato, is widely used in raw, cooked, or liquid forms because it contains nutritional compounds that are beneficial for human health, including carotenoids, lycopene, ascorbic acid, vitamins, and minerals. The tomato is perhaps the most widely studied fruit, especially with respect to its cardioprotective effects. In this study, we aimed to identify the anti-inflammatory mechanisms by which the tomato elicits its anti-inflammatory properties. We treated murine macrophage RAW 264.7 cells with a tomato ethanol extract and performed various biochemical assays including nitric oxide inhibition, cell viability, RNA extraction, expression of pro-inflammatory mediators and cytokines, and immunoblotting, as well we assessed cell survival rates. Our results have shown for the first time that a tomato ethanol extract treatment can suppress nitric oxide production in a dose-dependent manner without cytotoxicity. Moreover, it inhibits the expression of pro-inflammatory mediators and cytokines and elicits its anti-inflammatory effects via the nuclear factor kappa-light-chain-enhancer of activated B cells ($NF-{\kappa}B$) and mitogen-activated protein kinase (MAPK) pathways. In addition, administration of tomato syrup potently rescued mice from septic shock induced by lipopolysaccharide injection. Collectively, our results elucidate details regarding the anti-inflammatory mechanisms of tomato.

• Biomolecules & Therapeutics
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• 제24권2호
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• pp.184-190
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• 2016

Rosa rugosa Thunb, a deciduous shrub of the genus Rosa, has been widely used to treat stomach aches, diarrhoea, pain, and chronic inflammatory disease in eastern Asia. In recent years, our research team has extensively studied the Rosa rugosa flower extract, and specifically undertook pharmacological experiments which have optimized the extraction process. Our methods have yielded a standard extract enriched in phenolic compounds, named PRE. Herein, we expand our efforts and evaluated the anti-inflammatory activity of PRE on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. PRE significantly inhibited production of nitric oxide (NO), prostaglandin $E_2(PGE_2)$, tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and interleukin $1{\beta}$ (IL-$1{\beta}$), as well as expression of their synthesizing enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase2 (COX-2). Furthermore, PRE inhibited activity of mitogen-activated protein kinases (MAPK) as well as nuclear factor-kappa B (NF-${\kappa}B$) signaling pathway. Our findings are the first to explain the anti-inflammatory mechanism by PRE in LPS-stimulated macrophages. Given these results, we propose that PRE has therapeutic potential in the prevention of inflammatory disorders.

• 동의생리병리학회지
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• 제25권1호
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• pp.65-70
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• 2011

Osteoclasts play a critical role in bone-related diseases such as osteoporosis and rheumatoid arthritis by resorbing the bone. Recently, natural products from plants have been extensively studied as therapeutic drugs to treat and prevent various diseases. Here, we examined the effects of rhizoma arisaematis on ostoclast differentiation and bone resorption. We showed that rhizoma arisaematis significantly suppressed receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL)-induced osteoclast differentiation in bone marrow-derived macrophages (BMMs) in a dose dependent manner but have little or no effect on the cytotoxicity of BMMs and RAW264.7 cells. We found that rhizoma arisaematis iarrow-ed the RANKL-induced c-Fos and nuclear factor of activated T cells (NFAT)c1, which is a master regulator of osteoclast differentiation. Furthermore, rhizoma arisaematis suppressed the mRNA expression of tartrate resistant-acid phosphatase and cathepsin K iaduced by RANKL in BMMs. in y chanistic studies, rhizoma arisaematis considerably iarrow-ed I-${\kappa}B$ degradation, which is a negative regulator of NF-${\kappa}B$, but iaduced the phosphderlation of p-38, ERK, and JNK.MMlso, we found that rhizoma arisaematis significantly iarrow-ed osteoclastic bone resorption. Taken tarether, our results suggest that rhizoma arisaematis suppresses osteoclast differentiation through down-regulatd the mRANKL-induced c-Fos and NFATc1 expression and iarrow-s bone resorption.