• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.14.1-14.14
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• 2018

The link between antibiotic treatment and IF-associated liver disease (IFALD) is unclear. Here, we study the effect of antibiotic treatment on bile acid (BA) metabolism and investigate the involved mechanisms. The results showed that pediatric IF patients with cholestasis had a significantly lower abundance of BA-biotransforming bacteria than patients without cholestasis. In addition, the BA composition was altered in the serum, feces, and liver of pediatric IF patients with cholestasis, as reflected by the increased proportion of primary BAs. In the ileum, farnesoid X receptor (FXR) expression was reduced in patients with cholestasis. Correspondingly, the serum FGF19 levels decreased significantly in patients with cholestasis. In the liver, the expression of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), increased noticeably in IF patients with cholestasis. In mice, we showed that oral antibiotics (gentamicin, GM or vancomycin, VCM) reduced colonic microbial diversity, with a decrease in both Gram-negative bacteria (GM affected Eubacterium and Bacteroides) and Gram-positive bacteria (VCM affected Clostridium, Bifidobacterium and Lactobacillus). Concomitantly, treatment with GM or VCM decreased secondary BAs in the colonic contents, with a simultaneous increase in primary BAs in plasma. Moreover, the changes in the colonic BA profile especially that of tauro-beta-muricholic acid ($T{\beta}MCA$), were predominantly associated with the inhibition of the FXR and further altered BA synthesis and transport. In conclusion, the administration of antibiotics significantly decreased the intestinal microbiota diversity and subsequently altered the BA composition. The alterations in BA composition contributed to cholestasis in IF patients by regulating FXR signaling.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1478-1487
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• 2019

Ulcerative colitis (UC), a chronic inflammatory bowel disease, substantially impacts patients' health-related quality of life. In this study, an effective strategy for discovering high-efficiency probiotics has been developed. First, in order to survive in the conditions of the stomach and intestine, high bile salt-resistant and strong acid-resistant strains were screened out from the fecal flora of healthy adults. Next, the probiotic candidates were rescreened by examining the induction ability of IL-10 (anti-inflammatory factor) production in dextran sodium sulfate (DSS)-induced colitis mice, and Lactobacillus sakei 07 (L07) was identified and selected as probiotic P. In the end, fourteen bifidobacterium strains isolated from stools of healthy males were examined for their antimicrobial activity. Bifidobacterium bifidum B10 (73.75% inhibition rate) was selected as probiotic B. Moreover, the colonic IL-6 and $TNF-{\alpha}$ expression of the DSS-induced colitis mice treated with L. sakei 07 (L07) - B. bifidum B10 combination (PB) significantly decreased and the IL-10 expression was up-regulated by PB compared to the DSS group. Furthermore, Bacteroidetes and Actinobacteria decreased and Firmicutes increased in the DSS group mice, significantly. More interestingly, the intestinal flora biodiversity of DSS colitis mice was increased by PB. Of those, the level of B. bifidum increased significantly. The Bacteriodetes/Firmicutes (B/F) ratio increased, and the concentration of homocysteine and LPS in plasma was down-regulated by PB in the DSS-induced colitis mice. Upon administration of PB, the intestinal permeability of the the DSS-induced colitis mice was decreased by approximately 2.01-fold. This method is expected to be used in high-throughput screening of the probiotics against colitis. In addition, the L. sakei 07 - B. bifidum B10 combination holds potential in UC remission by immunomodulatory and gut microbiota modulation.

• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1057-1065
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• 2023

Inflammatory bowel disease (IBD), a chronic inflammatory disease, results from dysregulation of the immune responses. Some lactic acid bacteria (LAB), including Lactobacillus, alleviate IBD through immunomodulation. In this study, the anti-colitis effect of LAB isolated from human breast milk was investigated in a mouse model induced acute colitis with 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS remarkably increased weight loss, colon shortening, and colonic mucosal proliferation, as well as the expression levels of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β. Oral administration of LAB isolated from human breast milk resulted in a reduction in TNBS-induced colon shortening, as well as induced cyclooxygenase (COX)-2, nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB). In addition, LAB suppressed inflammatory cytokines such as TNF-α, IL-6, and IL-1β, and thus showed an effect of suppressing the level of inflammation induced by TNBS. Furthermore, LAB alleviated gut microbiota dysbiosis, and inhibited intestinal permeability by increasing the expression of intestinal tight junction protein including ZO-1. Collectively, these results suggest that LAB isolated from human breast milk can be used as a functional food for colitis treatment by regulating NF-κB signaling, gut microbiota and increasing expression of intestinal tight junction protein.

• The Korean Journal of Food And Nutrition
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• v.37 no.3
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• pp.139-151
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• 2024

The objective of this study was to investigate the anticancer effects of EMPS (edible mushroom mycelium polysaccharide: Tremella fuciformis) in animal models with colorectal cancer induced by AOM/DSS. The experimental groups consisted of Nor (normal), NC (AOM/DSS), EMPS (EMPS 50, EMPS 100), and PC (Fluorouracil). The NC group had the highest number of colon tumors, whereas it was observed that tumor occurrence was significantly reduced in the EMPS consumption group. The expression of Bcl-2, an apoptosis inhibitor, was significantly lower in the EMPS 50 & 100 and PC groups. On the other hand, the mRNA gene expression of Bax, a factor that induces apoptosis, was significantly higher in the EMPS 50 & 100 and PC groups compared to the NC group. The mRNA expression levels of TNF-α and COX-2 significantly increased in the NC group, but showed a significant decrease in the EMPS and PC groups, indicating inhibition of the cancer-promoting response of cells. At the phylum level of the mice's intestinal microbial composition, the proportion of Bacteroidetes tended to decrease, while the proportion of Firmicutes tended to increase with EMPS administration. This suggests that changes in the gut microbiota caused by inflammation can be influenced by dietary intake.

• Journal of Applied Biological Chemistry
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• v.61 no.2
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• pp.165-172
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• 2018

Due to the recent economic development, the diet style has become more and more westernized in Korea, which increased the concern of our well-beings. Our well-beings are also associated with the gut microbiota which vary depending on the dietary intake. In this study, we compared gut microbiome shifted by two diets: high-fat diets (HFD) and low-fiber diet (LFD) based on 16S rRNA gene sequences using MiSeq. Compared to the control diet, LFD and HFD treatments significantly decreased species richness, while there was no difference in species evenness. Both diet treatments significantly increased the relative abundance of the Proteobacteria (p<0.05), especially the genus Sutterella. Bacteroidetes was significantly decreased in HFD groups, where the family S24-7 was decreased most. On the other hand, significant difference between HFD and LFD was seen among Firmicutes, where the abundance of family Lachnospiraceae was lower in LFD groups (p<0.05). PICRUSt-based metabolic difference analyses showed LFD treatment significantly decreased metabolisms of amino acid, carbohydrate and methane (p<0.01). In contrast, HFD significantly increased amino acid metabolism (p<0.05). Glycan biosynthesis and metabolism were significantly increased in both treatment groups (p<0.01). Our results suggest that long-term unbalanced dietary intakes induce gut dysbiosis, leading to metabolic and colonic disorders.