• Journal of Ginseng Research
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• v.43 no.2
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• pp.172-178
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• 2019

Inflammation is an innate immune response that protects the body from pathogens, toxins, and other dangers and is initiated by recognizing pathogen-associated molecular patterns or danger-associated molecular patterns by pattern-recognition receptors expressing on or in immune cells. Intracellular pattern-recognition receptors, including nucleotide-binding oligomerization domain-like receptors (NLRs), absent in melanoma 2, and cysteine aspartate-specific protease (caspase)-4/5/11 recognize various pathogen-associated molecular patterns and danger-associated molecular patterns and assemble protein complexes called "inflammasomes." These complexes induce inflammatory responses by activating a downstream effector, caspase-1, leading to gasdermin D-mediated pyroptosis and the secretion of proinflammatory cytokines, such as interleukin $(IL)-1{\beta}$ and IL-18. Ginsenosides are natural steroid glycosides and triterpene saponins found exclusively in the plant genus Panax. Various ginsenosides have been identified, and their abilities to regulate inflammatory responses have been evaluated. These studies have suggested a link between ginsenosides and inflammasome activation in inflammatory responses. Some types of ginsenosides, including Rh1, Rg3, Rb1, compound K, chikusetsu saponin IVa, Rg5, and Rg1, have been clearly demonstrated to inhibit inflammatory responses by suppressing the activation of various inflammasomes, including the NLRP3, NLRP1, and absent in melanoma 2 inflammasomes. Ginsenosides have also been shown to inhibit caspase-1 and to decrease the expression of $IL-1{\beta}$ and IL-18. Given this body of evidence, the functional relationship between ginsenosides and inflammasome activation provides new insight into the understanding of the molecular mechanisms of ginsenoside-mediated antiinflammatory actions. This relationship also has applications regarding the development of antiinflammatory remedies by ginsenoside-mediated targeting of inflammasomes, which could be used to prevent and treat inflammatory diseases.

• BMB Reports
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• v.54 no.5
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• pp.260-265
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• 2021

Dysregulation of inflammation induced by noninfectious stress conditions, such as nutrient deprivation, causes tissue damage and intestinal permeability, resulting in the development of inflammatory bowel diseases. We studied the effect of autophagy on cytokine secretion related to intestinal permeability under nutrient deprivation. Autophagy removes NLRP3 inflammasomes via ubiquitin-mediated degradation under starvation. When autophagy was inhibited, starvation-induced NLRP3 inflammasomes and their product, IL-1β, were significantly enhanced. A prolonged nutrient deprivation resulted in an increased epithelial mesenchymal transition (EMT), leading to intestinal permeability. Under nutrient deprivation, IL-17E/25, which is secreted by IL-1β, demolished the intestinal epithelial barrier. Our results suggest that an upregulation of autophagy maintains the intestinal barrier by suppressing the activation of NLRP3 inflammasomes and the release of their products, including pro-inflammatory cytokines IL-1β and IL-17E/25, under nutrient deprivation.

• IMMUNE NETWORK
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• v.12 no.6
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• pp.284-290
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• 2012

Innate immune cells sense and respond to the cytoplasmic infection of bacterial pathogens through NLRP3, NLRC4 or AIM2 inflammasome depending on the unique molecular pattern of invading pathogens. The infection of flagellin- or type III secretion system (T3SS)-containing Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) or Pseudomonas aeruginosa (P. aeruginosa) triggers NLRC4-dependent caspase-1 activation leading to the secretion of proinflammatory cytokines such as interleukin-1-beta (IL-$1{\beta}$) and IL-18. Previous studies have shown that apoptosis-associated speck-like protein containing a CARD (ASC) is also required for Salmonella-induced caspase-1 activation, but it is still unclear how ASC contributes to the activation of NLRC4 inflammasome in response to S. typhimurium infection. In this study, we demonstrate that S. typhimurium triggers the formation of ASC oligomer in a potassium depletion-independent manner as determined by in vitro crosslinking and in situ fluorescence imaging. Remarkably, inhibition of potassium efflux failed to block Salmonella-promoted caspase-1 activation and macrophage cell death. These results collectively suggest that ASC is substantially oligomerized to facilitate the activation of caspase-1 in response to S. typhimurium infection. Contrary to NLRP3 inflammasome, intracellular potassium depletion is not critical for NLRC4 inflammasome signaling by S. typhimurium.

• Biomedical Science Letters
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• v.25 no.1
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• pp.92-98
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• 2019

Metformin is a drug used for the treatment of diabetes and is associated with anti-inflammatory reaction, but the underlying mechanism is unclear. In this study, we investigated the effect of metformin on the inflammatory response in BV-2 microglial cells induced by lipopolysaccharide (LPS) and S100 calcium-binding protein A8 (S100A8). The results revealed that metformin significantly attenuated several inflammatory responses in BV-2 microglial cells, including the secretion of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$ and interleukin (IL)-6, involved in the activation of Beclin-1, a crucial regulator of autophagy. In addition, metformin inhibited the LPS-induced phosphorylation of ERK. Metformin also suppressed the activation of NOD-like receptor pyrin domain containing 3 inflammasomes composed of NLRP3, caspase-1, and apoptosis-associated speck like protein containing a caspase recruitment domain, which are involved in the innate immune response. Notably, metformin decreased the secretion of S100A8-induced IL-6 production. These findings suggest that metformin alleviates the neuroinflammatory response via autophagy activation.

• Journal of Life Science
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• v.29 no.5
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• pp.607-613
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• 2019

The purpose of this study was to investigate the effects of either chrysin or exercise on the inflammasome and thermogenic markers in the livers of high-fat fed mice. C57BL/6 mice were randomly assigned to four groups: normal diet control (NC; n=5), high-fat diet control (HC; n=5), high-fat diet with chrysin (Hch; n=5), and high-fat diet with moderate exercise (HME; n=5). The mice were fed a high-fat diet (60% of calories from fat) or normal diet (18% of calories from fat). Chrysin was supplemented orally as 50mg/kg/day dissolved in a 0.1ml solution of dimethyl sulfoxide. The exercised mice ran on a treadmill at 12-20 m/min for 30-60 min/day, 5 times/week, for 16 weeks. After the intervention, the epididymal fat and liver weights were significantly decreased in the HME group compared with HC and Hch groups. The adipocyte size was effectively decreased in the Hch and HME groups compared with the HC group. The inflammasome markers NLRP3, $IL-1{\beta}$, and caspase1 were significantly decreased in the Hch and HME groups compared with the HC group. The thermogenic markers $PGC-1{\alpha}$ and BMP7 were significantly lower in the HC than in the NC group. However, the HME group showed an increase in the thermogenic markers. In conclusion, chrysin and moderate exercise have positive effects on obese metabolic complications induced by high-fat diets by reducing inflammasome genes. However, chrysin supplementation had no effect on thermogenic gene expression. Moderate exercise would therefore seem to be more effective in controlling obesity-induced metabolic deregulation.

• Journal of Pharmacopuncture
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• v.25 no.4
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• pp.396-403
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• 2022

Objectives: Gout is an inflammatory arthritis of the joints and soft tissues occurring due to deposition of monosodium urate (MSU) crystals, which are caused by persistent hyperuricemia. Soyeom pharmacopuncture is one treatment method that has been traditionally used for pain management in Oriental medicine. However, studies on its effect in reducing gout pain have been insufficient. Therefore, we selected Soyeom pharmacopuncture among natural products used in Korea as the new target of our study. Methods: The effects of Soyeom pharmacopuncture were examined in mouse models of acute gout induced by injection of MSU crystals into footpads. IL-1β, IL-6, and TNF-α production were examined by immunoblotting and enzyme-linked immunosorbent assay as hallmarks of NLRP3 inflammasome and cytokine activation. Results: Soyeom pharmacopuncture reduced foot edema in gout-induced mice, as well as IL-1β, nitrite, IL-6, and TNF-α production. Moreover, Soyeom pharmacopuncture also reduced MSU-induced gout inflammatory gene expressions, specifically those in the NF-kB pathway. Conclusion: Pharmacopuncture may serve as a new solution for other inflammatory diseases as well. Through active follow-up studies, we could thoroughly understand the clinical value of Soyeom pharmacopuncture.

• BMB Reports
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• v.52 no.10
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• pp.613-618
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• 2019

Microglial cells are known as the main immune cells in the central nervous system, both regulating its immune response and maintaining its homeostasis. Furthermore, the antioxidant ${\alpha}-lipoic$ acid (LA) is a recognized therapeutic drug for diabetes because it can easily invade the blood-brain barrier. This study investigated the effect of ${\alpha}-LA$ on the inflammatory response in lipopolysaccharide (LPS)-treated BV-2 microglial cells. Our results revealed that ${\alpha}-LA$ significantly attenuated several inflammatory responses in BV-2 microglial cells, including pro-inflammatory cytokines, such as tumor necrosis $factor-{\alpha}$ and interleukin (IL)-6, and other cytotoxic molecules, such as nitric oxide and reactive oxygen species. In addition, ${\alpha}-LA$ inhibited the LPS-induced phosphorylation of ERK and p38 and its pharmacological properties were facilitated via the inhibition of the nuclear factor kappa B signaling pathway. Moreover, ${\alpha}-LA$ suppressed the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes, multiprotein complexes consisting of NLRP3 and caspase-1, which are involved in the innate immune response. Finally, ${\alpha}-LA$ decreased the genes accountable for the M1 phenotype, $IL-1{\beta}$ and ICAM1, whereas it increased the genes responsible for the M2 phenotype, MRC1 and ARG1. These findings suggest that ${\alpha}-LA$ alleviates the neuroinflammatory response by regulating microglial polarization.

• IMMUNE NETWORK
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• v.21 no.5
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• pp.36.1-36.16
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• 2021

Peroxiredoxins (Prxs) are ubiquitously expressed peroxidases that reduce hydrogen peroxide or alkyl peroxide production in cells. Prxs are released from cells in response to various stress conditions, and they function as damage-associated molecular pattern molecules. However, the secretory mechanism of Prxs and their roles have not been elucidated. Thus, we aimed to determine whether inflammasome activation is a secretory mechanism of Prxs and subsequently identify the effect of the secreted Prxs on activation of the classical complement pathway. Using J774A.1, a murine macrophage cell line, we demonstrated that NLRP3 inflammasome activation induces Prx1, Prx2, Prx5, and Prx6 secretion in a caspase-1 dependent manner. Using HEK293T cells with a transfection system, we revealed that the release of Prx1 and Prx2 relies on gasdermin-D (GSDMD)-mediated secretion. Next, we confirmed the binding of both Prx1 and Prx2 to C1q; however, only Prx2 could induce the C1q-mediated classical complement pathway activation. Collectively, our results suggest that inflammasome activation is a secretory mechanism of Prxs and that GSDMD is a mediator of their secretion. Moreover, secreted Prx1 and Prx2 bind with C1q, but only Prx2 mediates the classical complement pathway activation.

• Journal of Life Science
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• v.27 no.12
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• pp.1462-1469
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• 2017

The purpose of this study was to investigate the effects of resveratrol supplementation on inflammasome, inflammation, and macrophage markers in subcutaneous adipose tissue of high-fat-diet-induced obese mice. C57BL/6 mice were randomly assigned to three groups: normal diet control (NC; n=10), high-fat diet control (HC; n=10), or high fat with resveratrol (HRE; n=10) group. The mice were fed a high-fat diet (60% of calories from fat) or normal diet (18% of calories from fat). Resveratrol dissolved in a 0.1ml solution of dimethyl sulfoxide was supplemented orally at 25 mg/kg body weight. After 15 weeks, the body weight was significantly higher in the high-fat diet group than in the normal diet group. The inflammasome markers NLRP3, ASC, and caspase1 were significantly lower in the HRE group than in the HC group. The levels of an inflammation marker, IL-18, were also significantly lower in the HRE group than in the NC and HC groups. The levels of macrophage markers F480 and CD86 were significantly lower in the HRE group than in the HC group. The levels of the M2 macrophage marker CD206 were significantly decreased in the HC and HRE groups. Resveratrol had a positive effect on ameliorating the complications of high fat diet-induced obesity by reducing inflammasome and M1 macrophage gene expressions. However, resveratrol supplementation did not reduce inflammation gene expression.

• Biomedical Science Letters
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• v.19 no.3
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• pp.173-179
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• 2013

Since the identification and characterization of toll-like receptors (TLR) in Drosophila, numerous scientific studies have examined the role of TLRs in host innate immunity. Recent studies have suggested a convergence of the nuclear factor kappa B (NF-${\kappa}B$) signaling and cytokine production regulated by the cytosolic elicitor known as NLRs (nucleotide-binding domain and leucine-rich repeat containing domain receptors) as a key modulator in inflammatory diseases. Among the NLRs, NOD1 and NOD2 have been intensively investigated for its role in inflammatory bowel disease (IBD). On the other hand, NLRs such as NLRP3, NLRP1, and NLRC4 (also known as IPAF) have been identified to form the inflammasome to activate downstream signaling molecules in response to pathogenic microbes. There is evidence to suggest that substantial crosstalk exists for the TLR and NLR signaling pathway in response to pathogen associated molecular pattern (PAMP). However, the substrate and the mechanistic role of NLRs are largely unknown in innate immune response. Understanding the signaling mechanisms by which NLRs recognize PAMP and other danger signals will shed light on elucidating the pathogenesis of various human inflammatory diseases such as IBD.