• Biomolecules & Therapeutics
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• v.32 no.4
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• pp.403-423
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• 2024

The human gastrointestinal (GI) tract houses a diverse microbial community, known as the gut microbiome comprising bacteria, viruses, fungi, and protozoa. The gut microbiome plays a crucial role in maintaining the body's equilibrium and has recently been discovered to influence the functioning of the central nervous system (CNS). The communication between the nervous system and the GI tract occurs through a two-way network called the gut-brain axis. The nervous system and the GI tract can modulate each other through activated neuronal cells, the immune system, and metabolites produced by the gut microbiome. Extensive research both in preclinical and clinical realms, has highlighted the complex relationship between the gut and diseases associated with the CNS, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This review aims to delineate receptor and target enzymes linked with gut microbiota metabolites and explore their specific roles within the brain, particularly their impact on CNS-related diseases.

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.927-937
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• 2022

To confirm the therapeutic effect of the water extract from Ecklonia cava (WEE) against PM_2.5 induced systemic health damage, we evaluated gut health with a focus on the microbiota and metabolites. Systemic damage in mice was induced through PM_2.5 exposure for 12 weeks in a whole-body chamber. After exposure for 12 weeks, body weight and food intake decreased, and WEE at 200 mg/kg body weight (mpk) alleviated these metabolic efficiency changes. In addition, PM_2.5 induced changes in the length of the colon and fecal water content. The administration of the WEE at 200 mpk oral dose effectively reduced changes in the colon caused by PM_2.5 exposure. We also attempted to confirm whether the effect of the WEE is mediated via regulation of the microbiota-gut-brain axis in mice with PM_2.5 induced systemic damage. We examined changes in the fecal microbiota and gut metabolites such as short-chain fatty acids (SCFAs) and kynurenine metabolites. In the PM_2.5 exposed group, a decrease in the abundance of Lactobacillus (Family: Lactobacillaceae) and an increase in the abundance of Alistipes (Family: Rikenellaceae) were observed, and the administration of the WEE showed a beneficial effect on the gut microbiota. In addition, the WEE effectively increased the levels of SCFAs (acetate, propionate, and butyrate). Furthermore, kynurenic acid (KYNA), which is a critical neuroprotective metabolite in the gut-brain axis, was increased by the administration of the WEE. Our findings suggest that the WEE could be used as a potential therapeutic against PM_2.5 induced health damage by regulating gut function.

• Journal of Animal Science and Technology
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• v.64 no.5
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• pp.937-949
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• 2022

Health concern of dogs is the most important issue for pet owners. People who have companied the dogs long-term provide the utmost cares for their well-being and healthy life. Recently, it was revealed that the population and types of gut microbiota affect the metabolism and immunity of the host. However, there is little information on the gut microbiome of dogs. Hericium erinaceus (H. erinaceus; HE) is one of the well-known medicinal mushrooms and has multiple bioactive components including polyphenol, β-glucan, polysaccharides, ergothioneine, hericerin, erinacines, etc. Here we tested a pet food that contained H. erinaceus for improvement in the gut microbiota environment of aged dogs. A total of 18 dogs, each 11 years old, were utilized. For sixteen weeks, the dogs were fed with 0.4 g of H. erinaceus (HE-L), or 0.8 g (HE-H), or without H. erinaceus (CON) per body weight (kg) with daily diets (n = 6 per group). Taxonomic analysis was performed using metagenomics to investigate the difference in the gut microbiome. Resulting from principal coordinates analysis (PCoA) to confirm the distance difference between the groups, there was a significant difference between HE-H and CON due to weighted Unique fraction metric (Unifrac) distance (p = 0.047), but HE-L did not have a statistical difference compared to that of CON. Additionally, the result of Linear discriminate analysis of effect size (LEfSe) showed that phylum Bacteroidetes in HE-H and its order Bacteroidales increased, compared to that of CON, Additionally, phylum Firmicutes in HE-H, and its genera (Streptococcus, Tyzzerella) were reduced. Furthermore, at the family level, Campylobacteraceae and its genus Campylobacter in HE-H was decreased compared to that of CON. Summarily, our data demonstrated that the intake of H. erinaceus can regulate the gut microbial community in aged dogs, and an adequate supply of HE on pet diets would possibly improve immunity and anti-obesity on gut-microbiota in dogs.

• Korean Journal of Exercise Nutrition
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• v.25 no.2
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• pp.1-7
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• 2021

[Purpose] Recent studies have shown that COVID-19 is often associated with altered gut microbiota composition and reflects disease severity. Furthermore, various reports suggest that the interaction between COVID-19 and host-microbiota homeostasis is mediated through the modulation of microRNAs (miRNAs). Thus, in this review, we aim to summarize the association between human microbiota and miRNAs in COVID-19 pathogenesis. [Methods] We searched for the existing literature using the keywords such "COVID-19 or microbiota," "microbiota or microRNA," and "COVID-19 or probiotics" in PubMed until March 31, 2021. Subsequently, we thoroughly reviewed the articles related to microbiota and miRNAs in COVID-19 to generate a comprehensive picture depicting the association between human microbiota and microRNAs in the pathogenesis of COVID-19. [Results] There exists strong experimental evidence suggesting that the composition and diversity of human microbiota are altered in COVID-19 patients, implicating a bidirectional association between the respiratory and gastrointestinal tracts. In addition, SARS-CoV-2 encoded miRNAs and host cellular microRNAs modulated by human microbiota can interfere with viral replication and regulate host gene expression involved in the initiation and progression of COVID-19. These findings suggest that the manipulation of human microbiota with probiotics may play a significant role against SARS-CoV-2 infection by enhancing the host immune system and lowering the inflammatory status. [Conclusion] The human microbiota-miRNA axis can be used as a therapeutic approach for COVID-19. Hence, further studies are needed to investigate the exact molecular mechanisms underlying the regulation of miRNA expression in human microbiota and how these miRNA profiles mediate viral infection through host-microbe interactions.

• BMB Reports
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• v.50 no.11
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• pp.578-583
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• 2017

Programmed cell death-1 (PD-1) is a coinhibitory molecule and plays a pivotal role in immune regulation. Here, we demonstrate a role for PD-1 in pathogenesis of inflammatory bowel disease (IBD). Wild-type (WT) mice had severe wasting disease during experimentally induced colitis, while mice deficient for PD-1 ($PD-1^{-/-}$) did not develop colon inflammation. Interestingly, $PD-1^{-/-}$ mice cohoused with WT mice became susceptible to colitis, suggesting that resistance of $PD-1^{-/-}$ mice to colitis is dependent on their gut microbiota. 16S rRNA gene-pyrosequencing analysis showed that $PD-1^{-/-}$ mice had altered composition of gut microbiota with significant reduction in Rikenellaceae family. These altered colon bacteria of $PD-1^{-/-}$ mice induced less amount of inflammatory mediators from colon epithelial cells, including interleukin (IL)-6, and inflammatory chemokines. Taken together, our study indicates that PD-1 expression is involved in the resistance to experimental colitis through altered bacterial communities of colon.

• Development and Reproduction
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• v.26 no.4
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• pp.145-153
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• 2022

The gut microbiota is involved in the maintenance of physiological homeostasis and is now recognized as a regulator of many diseases. Although germ-free mouse models are the standard for microbiome studies, mice with antibiotic-induced sterile intestines are often chosen as a fast and inexpensive alternative. Pathophysiological changes in the gut microbiome have been demonstrated, but there are no reports so far on how such alterations affect the bacterial composition of the uterus. Here we examined changes in uterine microbiota as a result of gut microbiome disruption in an antibiotics-based sterile-uterus mouse model. Sterility was induced in 6-week-old female mice by administration of a combination of antibiotics, and amplicons of a bacteria marker gene (16S rRNA) were sequenced to decipher bacterial community structures in the uterus. At the phylum-level, Proteobacteria, Firmicutes, and Actinobacteria were found to be dominant, while Ralstonia, Escherichia, and Prauserella were the major genera. Quantitative comparisons of the microbial contents of an antibiotic-fed and a control group revealed that the treatment resulted in the reduction of bacterial population density. Although there was no significant difference in bacterial community structures between the two animal groups, β-diversity analysis showed a converged profile of uterus microbiotain the germ-free model. These findings suggest that the induction of sterility does not result in changes in the levels of specific taxa but in a reduction of individual variations in the mouse uterus microbiota, accompanied by a decrease in overall bacterial population density.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1781-1794
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• 2018

Objective: This meta-analysis was conducted to evaluate the overall effect of direct-fed microbial (DFM) or probiotic supplementation on the log concentrations of culturable gut microbiota in broiler chickens. Methods: Relevant studies were collected from PubMed, SCOPUS, Poultry Science Journal, and Google Scholar. The studies included controlled trials using DFM supplementation in broiler chickens and reporting log concentrations of the culturable gut microbiota. The overall effect of DFM supplementation was determined using standardized mean difference (SMD) with a random-effects model. Subgroups were analyzed to identify pre-specified characteristics possibly associated with the heterogeneity of the results. Risk of bias and publication bias were assessed. Results: Eighteen taxa of the culturable gut microbiota were identified from 42 studies. The overall effect of DFM supplementation on the log concentrations of all 18 taxa did not differ significantly from the controls (SMD = -0.06, 95% confidence interval [-0.16, 0.04], p = 0.228, $I^2=85%$, n = 699 comparisons), but the 18 taxa could be further classified into three categories by the direction of the effect size: taxa whose log concentrations did not differ significantly from the controls (category 1), taxa whose log concentrations increased significantly with DFM supplementation (category 2), and taxa whose log concentrations decreased significantly with DFM supplementation (category 3). Category 1 comprised nine taxa, including total bacterial counts. Category 2 comprised four taxa: Bacillus, Bifidobacterium, Clostridium butyricum, and Lactobacillus. Category 3 comprised five taxa: Clostridium perfringens, coliforms, Escherichia coli, Enterococcus, and Salmonella. Some characteristics identified by the subgroup analysis were associated with result heterogeneity. Most studies, however, were present with unclear risk of bias. Publication bias was also identified. Conclusion: DFM supplementation increased the concentrations of some beneficial bacteria (e.g. Bifidobacterium and Lactobacillus) and decreased those of some detrimental bacteria (e.g. Clostridium perfringens and Salmonella) in the guts of broiler chickens.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1391-1400
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• 2019

Canine parvoviral enteritis (PVE) is an important intestinal disease of the puppies; however, the potential impact of the canine parvovirus (CPV) on the gut microbiota has not been investigated. Therefore, the aim of this study was to evaluate the gut microbial shifts in puppies naturally infected with CPV. Fecal samples were collected from healthy dogs and those diagnosed with PVE at 4, 6, 8, and 12 weeks of age. The distal gut microbiota of dogs was characterized using Illumina MiSeq sequencing of the bacterial 16S rRNA genes. The sequence data were analyzed using QIIME with an Operational Taxonomic Unit definition at a similarity cutoff of 97%. Our results showed that the CPV was associated with significant microbial dysbiosis of the intestinal microbiota. Alpha diversity and species richness and evenness in dogs with PVE decreased compared to those of healthy dogs. At the phylum level, the proportion of Proteobacteria was significantly enriched in dogs with PVE while Bacteroidetes was significantly more abundant in healthy dogs (p < 0.05). In dogs with PVE, Enterobacteriaceae was the most abundant bacterial family accounting for 36.44% of the total bacterial population compared to only 0.21% in healthy puppies. The two most abundant genera in healthy dogs were Prevotella and Lactobacillus and their abundance was significantly higher compared to that of dogs with PVE (p < 0.05). These observations suggest that disturbances of gut microbial communities were associated with PVE in young dogs. Evaluation of the roles of these bacterial groups in the pathophysiology of PVE warrants further studies.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1195-1204
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• 2015

Increasing evidence suggests that gut microbiota underpin the development of health and longevity. However, our understanding of what influences the composition of this community of the longevous has not been adequately described. Therefore, illumina sequencing analysis was performed on the gut microbiota of centenarians (aged 100-108 years; RC) and younger elderlies (aged 85-99 years; RE) living in Bama County, Guangxi, China and the elderlies (aged 80-92 years; CE) living in Nanning City, Guangxi, China. In addition, their diet was monitored using a semiquantitative dietary questionary (FFQ 23). The results revealed the abundance of Roseburia and Escherichia was significantly greater, whereas that of Lactobacillus, Faecalibacterium, Parabacteroides, Butyricimonas, Coprococcus, Megamonas, Mitsuokella, Sutterella, and Akkermansia was significantly less in centenarians at the genus level. Both clustering analysis and UniFraq distance analysis showed structural segregation with age and diet among the three populations. Using partial least square discriminate analysis and redundancy analysis, we identified 33 and 34 operational taxonomic units (OTUs) as key OTUs that were significantly associated with age and diet, respectively. Age-related OTUs were characterized as Ruminococcaceae, Clostridiaceae, and Lachnospiraceae, and the former two were increased in the centenarians; diet-related OTUs were classified as Bacteroidales, Lachnospiraceae, and Ruminococcaceae. The former two were deceased, whereas the later one was increased, in the high-fiber diet. The age and high-fiber diet were concomitant with changes in the gut microbiota of centenarians, suggesting that age and high-fiber diet can establish a new structurally balanced architecture of gut microbiota that may benefit the health of centenarians.

• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1287-1298
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• 2024

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that is currently difficult to treat effectively. Both Bacillus natto (BN) and ginseng-soluble dietary fiber (GSDF) are anti-inflammatory and helps sustain the intestinal barrier. In this study, the protective effects and mechanism of the combination of B. natto JLCC513 and ginseng-soluble dietary fiber (BG) in DSS-induced UC mice were investigated. Intervention with BG worked better than taking BN or GSDF separately, as evidenced by improved disease activity index, colon length, and colon injury and significantly reduced the levels of oxidative and inflammatory factors (LPS, ILs, and TNF-α) in UC mice. Further mechanistic study revealed that BG protected the intestinal barrier integrity by maintaining the tight junction proteins (Occludin and Claudin1) and inhibited the LPS/TLR4/NF-κB pathway in UC mice. In addition, BG increased the abundance of beneficial bacteria such as Bacteroides and Turicibacter and reduced the abundance of harmful bacteria such as Allobaculum in the gut microbiota of UC mice. BG also significantly upregulated genes related to linoleic acid metabolism in the gut microbiota. These BG-induced changes in the gut microbiota of mice with UC were significantly correlated with changes in pathological indices. In conclusion, this study demonstrated that BG exerts protective effect against UC by regulating the LPS/TLR4/NF-κB pathway and the structure and metabolic function of gut microbiota. Thus, BG can be potentially used in intestinal health foods to treat UC.