• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1896-1904
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• 2020

Muscle atrophy, characterized by a reduced number and size of myofibers, occurs due to immobilization, aging, and several chronic diseases. Leonurus japonicus, belonging to the Labiatae family, is widely used as a traditional medicine in Korea, China, and Japan. Previous studies have reported that L. japonicus has various physiological activities, such as anti-bacteria, anti-cancer, and liver protection. Leonurine, which is a major bioactive in L. japonicas, is known to possess biological effects including anti-inflammation, anti-fibrosis, anti-angiogenesis, and anti-diabetes. However, the preventive effects of L. japonicas and leonurine on muscle have not been reported. The current study aimed to determine the inhibitory effects of standardized L. japonicus extract (LJE) and leonurine on muscle atrophy by clarifying their underlying molecular mechanisms in tumor necrosis factor-alpha (TNF-α)-stimulated L6 myotubes. LJE and leonurine stimulated the phosphatidylinositol 3-kinase/Akt pathway that was reduced by TNF-α treatment. LJE and leonurine not only increased the mammalian target of rapamycin pathway for protein anabolism but also decreased the mRNA expression of E3 ubiquitin ligases by blocking the translocation of Forkhead box O, which is closely linked with proteolysis. Additionally, LJE and leonurine alleviated inflammatory responses by downregulating TNF-α and interleukin-6 mRNA expression and reducing the protein expression of nuclear factor-kappa B, a major transcriptional factor of proinflammatory cytokines. Collectively, LJE and leonurine have potential as therapeutic candidates for inhibiting the development of skeletal muscle atrophy by activating the PI3K/Akt pathway and reducing inflammatory responses.

• BMB Reports
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• v.54 no.3
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• pp.182-187
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• 2021

Leukotriene B4 (LTB4) is a lipid mediator of inflammation that is generated from arachidonic acid via the 5-lipoxygenase pathway. Previous studies have reported that the receptors of LTB4, BLT1, and BLT2 play mediatory roles in the allergic airway inflammation induced by ovalbumin (OVA). However, considering that house dust mites (HDMs) are the most prevalent allergen and well-known risk factor for asthmatic allergies, we are interested in elucidating the contributory roles of BLT1/2 in HDM-induced allergic airway inflammation. Our aim in this study was to investigate whether BLT1/2 play any roles in HDM-induced allergic airway inflammation. In this study, we observed that the levels of ligands for BLT1/2 [LTB4 and 12(S)-HETE (12(S)-hydroxyeicosatetraenoic acid)] were significantly increased in bronchoalveolar lavage fluid (BALF) after HDM challenge. Blockade of BLT1 or BLT2 as well as of 5-lipoxygenase (5-LO) or 12-lipoxygenase (12-LO) markedly suppressed the production of TH2 cytokines (IL-4, IL-5, and IL-13) and alleviated lung inflammation and mucus secretion in an HDM-induced eosinophilic airway-inflammation mouse model. Together, these results indicate that the 5-/12-LO-BLT1/2 cascade plays a role in HDM-induced airway inflammation by mediating the production of TH2 cytokines. Our findings suggest that BLT1/2 may be a potential therapeutic target for patients with HDM-induced allergic asthma.

• Journal of Radiation Protection and Research
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• v.45 no.4
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• pp.163-170
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• 2020

Background: Gut microflora contributes to the nutritional metabolism of the host and to strengthen its immune system. However, if the intestinal barrier function of the living body is destroyed by radiation exposure, the intestinal bacteria harm the health of the host and cause sepsis. Therefore, this study aims to trace short-term radiation-induced changes in the mouse gut microflora-dominant bacterial genus, and analyze the degree of intestinal epithelial damage. Materials and Methods: Mice were irradiated with 0, 2, 4, 8 Gy X-rays, and the gut microflora and intestinal epithelial changes were analyzed 72 hours later. Five representative genera of Actinobacteria, Firmicutes, and Bacteroidetes were analyzed in fecal samples, and the intestine was pathologically analyzed by Hematoxylin-Eosin and Alcian blue staining. In addition, DNA fragmentation was evaluated by the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Results and Discussion: The small intestine showed shortened villi and reduced number of goblet cells upon 8 Gy irradiation. The large intestine epithelium showed no significant morphological changes, but the number of goblet cells were reduced in a radiation dose-dependent manner. Moreover, the small intestinal epithelium of 8 Gy-irradiated mice showed significant DNA damaged, whereas the large intestine epithelium was damaged in a dose-dependent manner. Overall, the large intestine epithelium showed less recovery potential upon radiation exposure than the small intestinal epithelium. Analysis of the intestinal flora revealed fluctuations in lactic acid bacteria excretion after irradiation regardless of the morphological changes of intestinal epithelium. Altogether, it became clear that radiation exposure could cause an immediate change of their excretion. Conclusion: This study revealed changes in the intestinal epithelium and intestinal microbiota that may pave the way for the identification of novel biomarkers of radiation-induced gastrointestinal disorders and develop new therapeutic strategies to treat patients with acute radiation syndrome.

• Biomolecules & Therapeutics
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• v.29 no.5
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• pp.492-497
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• 2021

Levels of sphingosine 1-phosphate (S1P), an intercellular signaling molecule, reportedly increase in the bronchoalveolar lavage fluids of patients with asthma. Although the type 4 S1P receptor, S1P₄ has been detected in mast cells, its functions have been poorly investigated in an allergic asthma model in vivo. S1P₄ functions were evaluated following treatment of CYM50358, a selective antagonist of S1P₄, in an ovalbumin-induced allergic asthma model, and antigen-induced degranulation of mast cells. CYM50358 inhibited antigen-induced degranulation in RBL-2H3 mast cells. Eosinophil accumulation and an increase of Th2 cytokine levels were measured in the bronchoalveolar lavage fluid and via the inflammation of the lungs in ovalbumin-induced allergic asthma mice. CYM50358 administration before ovalbumin sensitization and before the antigen challenge strongly inhibited the increase of eosinophils and lymphocytes in the bronchoalveolar lavage fluid. CYM50358 administration inhibited the increase of IL-4 cytokines and serum IgE levels. Histological studies revealed that CYM50358 reduced inflammatory scores and PAS (periodic acid-Schiff)-stained cells in the lungs. The pro-allergic functions of S1P₄ were elucidated using in vitro mast cells and in vivo ovalbumin-induced allergic asthma model experiments. These results suggest that S1P₄ antagonist CYM50358 may have therapeutic potential in the treatment of allergic asthma.

• Nutrition Research and Practice
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• v.16 no.2
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• pp.161-172
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• 2022

BACKGROUND/OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness. MATERIALS/METHODS: CD133⁺CD44⁺ HCT116 and CD133⁺CD44⁺ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133⁺CD44⁺ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors. RESULTS: BC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133⁺CD44⁺ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well. CONCLUSIONS: These results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.

• Journal of Ginseng Research
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• v.46 no.3
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• pp.444-453
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• 2022

Background: Compound K (CK) is among the protopanaxadiol (PPD)-type ginsenoside group, which produces multiple pharmacological effects. Herein, we examined the effects of CK on muscle atrophy under hyperlipidemic conditions along with its pro-myogenic effects. Further, the molecular pathways underlying the effects of CK on skeletal muscle have been justified. Methods: C2C12 myotubes were treated with palmitate and CK. C2C12 myoblasts were differentiated using CK for 4-5 days. For the in vivo experiments, CK was administered to mice fed on a high-fat diet for 8 weeks. The protein expression levels were analyzed using western blotting analysis. Target protein suppression was performed using small interfering (si) RNA transfection. Histological examination was performed using Jenner-Giemsa and H&E staining techniques. Results: CK treatment attenuated ER stress markers, such as eIF2a phosphorylation and CHOP expression and impaired myotube formation in palmitate-treated C2C12 myotubes and skeletal muscle of mice fed on HFD. CK treatment augmented AMPK along with autophagy markers in skeletal muscle cells in vitro and in vivo experiments. AMPK siRNA or 3-MA, an autophagy inhibitor, abrogated the impacts of CK in C2C12 myotubes. CK treatment augmented p38 and Akt phosphorylation, leading to an enhancement of C2C12 myogenesis. However, AMPK siRNA abolished the effects of CK in C2C12 myoblasts. Conclusion: These findings denote that CK prevents lipid-induced skeletal muscle apoptosis via AMPK/autophagy-mediated attenuation of ER stress and induction of myoblast differentiation. Therefore, we may suggest the use of CK as a potential therapeutic approach for treating muscle-wasting conditions associated with obesity.

• Journal of Ginseng Research
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• v.46 no.3
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• pp.367-375
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• 2022

Background: Short-term hydroponic-cultured ginseng (sHCG), which is 1-year-old ginseng seedlings cultivated for 4 weeks in a hydroponic system, is a functional food item with several biological effects. However, the optimal extraction conditions for sHCG, and the bioactivity of its extracts, have not been evaluated. Methods: Chlorogenic acid (CGA) and ginsenoside contents were evaluated in sHCG, white ginseng (WG), and red ginseng (RG) using high-performance liquid chromatography. Response surface methodology (RSM) was used to optimize the extraction conditions (temperature and ethanol concentration) to maximize the yield of dry matter, CGA, and four ginsenosides (Re, Rg₁, Rb₁, and Rd) from sHCG. The optimal extraction conditions were applied to pilot-scale production of sHCG extracts. The expression levels of tumor necrosis factor (TNF)-α/interferon (IFN)-γ-induced thymic and activation-regulated chemokines (TARC/CCL17) were measured after treatment with sHCG, WG, and RG extracts, and the effects of their bioactive compounds (CGA and four ginsenosides) on human skin keratinocytes (HaCaTs) were evaluated. Results: CGA and four ginsenosides, which are bioactive compounds of sHCG, significantly inhibited TNF-α/IFN-γ-induced TARC/CCL17 expression. The optimal sHCG extraction conditions predicted by the RSM models were 80 ℃ and 60% ethanol (v/v). The sHCG extracts produced at the pilot scale under optimal conditions greatly alleviated TNF-α/IFN-γ-induced TARC/CCL17 production compared with WG and RG extracts. Conclusions: Pesticide-free sHCG extracts, which contain high levels of CGA and the ginsenosides Re, Rg₁, Rb₁, and Rd as bioactive compounds, may have therapeutic potential for atopic diseases.

• Molecules and Cells
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• v.44 no.12
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• pp.893-899
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• 2021

BLT2 is a low-affinity receptor for leukotriene B₄, a potent lipid mediator of inflammation generated from arachidonic acid via the 5-lipoxygenase pathway. The aim of this study was to investigate whether BLT2 plays any role in sepsis, a systemic inflammatory response syndrome caused by infection. A murine model of cecal ligation and puncture (CLP)-induced sepsis was used to evaluate the role of BLT2 in septic inflammation. In the present study, we observed that the levels of ligands for BLT2 (LTB₄ [leukotriene B₄] and 12(S)-HETE [12(S)-hydroxyeicosatetraenoic acid]) were significantly increased in the peritoneal lavage fluid and serum from mice with CLP-induced sepsis. We also observed that the levels of BLT2 as well as 5-lipoxygenase (5-LO) and 12-LO, which are synthesizing enzymes for LTB₄ and 12(S)-HETE, were significantly increased in lung and liver tissues in the CLP mouse model. Blockade of BLT2 markedly suppressed the production of sepsis-associated cytokines (IL-6 [interleukin-6], TNF-α [tumor necrosis factor alpha], and IL-1β [interleukin-β] as well as IL-17 [interleukin-17]) and alleviated lung inflammation in the CLP group. Taken together, our results suggest that BLT2 cascade contributes to lung inflammation in CLP-induced sepsis by mediating the production of inflammatory cytokines. These findings suggest that BLT2 may be a potential therapeutic target for sepsis patients.

• Biomolecules & Therapeutics
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• v.30 no.1
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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 Veterinary Science
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• v.23 no.3
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• pp.41.1-41.15
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• 2022

Background: Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium. Objectives: This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue. Methods: We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis. Results: The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × 10⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses. Conclusions: This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.