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ABSTRACTIndole in the gut is formed from dietary tryptophan by a bacterial tryptophan-indole lyase. Indole not only triggers biofilm formation and antibiotic resistance in gut microbes but also contributes to the progression of kidney dysfunction after absorption by the intestine and sulfation in the liver. As tryptophan is an essential amino acid for humans, these events seem inevitable. Despite this, we show in a proof-of-concept study that exogenous indole can be converted to an immunomodulatory tryptophan metabolite, indole-3-lactic acid (ILA), by a previously unknown microbial metabolic pathway that involves tryptophan synthase β subunit and aromatic lactate dehydrogenase. Selected bifidobacterial strains converted exogenous indole to ILA via tryptophan (Trp), which was demonstrated by incubating the bacterial cells in the presence of (2-13C)-labeled indole and l-serine. Disruption of the responsible genes variedly affected the efficiency of indole bioconversion to Trp and ILA, depending on the strains. Database searches against 11,943 bacterial genomes representing 960 human-associated species revealed that the co-occurrence of tryptophan synthase β subunit and aromatic lactate dehydrogenase is a specific feature of human gut-associated Bifidobacterium species, thus unveiling a new facet of bifidobacteria as probiotics. Indole, which has been assumed to be an end-product of tryptophan metabolism, may thus act as a precursor for the synthesis of a host-interacting metabolite with possible beneficial activities in the complex gut microbial ecosystem.

Examining how host cells affect metabolic behaviors of probiotics is pivotal to better understand the mechanisms underlying the probiotic efficacy in vivo. However, studies to elucidate the interaction between probiotics and host cells, such as intestinal epithelial cells, remain limited. Therefore, in this study, we performed a comprehensive metabolome analysis of a co-culture containing Bifidobacterium breve MCC1274 and induced pluripotent stem cells (iPS)-derived small intestinal-like cells. In the co-culture, we observed a significant increase in several amino acid metabolites, including indole-3-lactic acid (ILA) and phenyllactic acid (PLA). In accordance with the metabolic shift, the expression of genes involved in ILA synthesis, such as transaminase and tryptophan synthesis-related genes, was also elevated in B. breve MCC1274 cells. ILA production was enhanced in the presence of purines, which were possibly produced by intestinal epithelial cells (IECs). These findings suggest a synergistic action of probiotics and IECs, which may represent a molecular basis of host-probiotic interaction in vivo.

Blautia is a genus of anaerobic bacteria that is widely distributed in the mammalian gut. Recently, an increasing body of research has demonstrated a link between this genus and human health, suggesting applications as a novel probiotic strain. Moreover, we have previously shown that 2′-fucosyllactose (2′-FL), a major component of human milk oligosaccharides, increases the relative abundance of Blautia sp., particularly Blautia wexlerae, in the cultured fecal microbiota of healthy adults using a pH-controlled single-batch fermenter. However, the effects of 2′-FL on Blautia proliferation vary among individuals. In this study, we assessed the impact of the intrinsic gut microbiota on the prebiotic effects of 2′-FL. Metagenomic analysis of feces collected from all donors showed that the homolog of the intracellular GH95 α-l-fucosidase gene was considerably enriched in two non-responders (individuals who showed no increase in Blautia proliferation), whereas the homologous genes encoding extracellular α-l-fucosidase were more abundant in responders, suggesting that lactose and fucose released into the environment could be substrates mediating the growth of Blautia. In vitro assays confirmed the ability of B. wexlerae to utilize the two carbohydrates but not 2′-FL. We also observed that B. wexlerae utilized fucose released from 2′-FL by Bifidobacterium bifidum, which possessed extracellular GH95 α-l-fucosidase, in co-cultures of these two organisms. Finally, increasing the proportion of extracellular GH95 by the addition of a B. bifidum strain led to Blautia proliferation by 2′-FL in fecal cultures of the two non-responders. These findings provided valuable perspectives on individualized nutritional approaches to properly control the gut microbiota. Future clinical trials are needed to obtain further insights into the characteristics of responders vs. non-responders.

Abstract Background Inter-individual variations in gut microbiota composition are observed even among healthy populations. The gut microbiota may exhibit a unique composition depending on the country of origin and race of individuals. To comprehensively understand the link between healthy gut microbiota and host state, it is beneficial to conduct large-scale cohort studies. The aim of the present study was to elucidate the integrated and non-redundant factors associated with gut microbiota composition within the Japanese population by 16S rRNA sequencing of fecal samples and questionnaire-based covariate analysis. Results A total of 1596 healthy Japanese individuals participated in this study via two independent cohorts, NIBIOHN cohort (n = 954) and MORINAGA cohort (n = 642). Gut microbiota composition was described and the interaction of these microorganisms with metadata parameters such as anthropometric measurements, bowel habits, medical history, and lifestyle were obtained. Thirteen genera, including Alistipes, Anaerostipes, Bacteroides, Bifidobacterium, Blautia, Eubacterium halli group, Faecalibacterium, Fusicatenibacter, Lachnoclostridium, Parabacteroides, Prevotella_9, Roseburia, and Subdoligranulum were predominant among the two cohorts. On the basis of univariate analysis for overall microbiome variation, 18 matching variables exhibited significant association in both cohorts. A stepwise redundancy analysis revealed that there were four common covariates, Bristol Stool Scale (BSS) scores, gender, age, and defecation frequency, displaying non-redundant association with gut microbial variance. Conclusions We conducted a comprehensive analysis of gut microbiota in healthy Japanese individuals, based on two independent cohorts, and obtained reliable evidence that questionnaire-based covariates such as frequency of bowel movement and specific dietary habit affects the microbial composition of the gut. To our knowledge, this was the first study to investigate integrated and non-redundant factors associated with gut microbiota among Japanese populations.

Yoshida et al. investigate the role of an ABC transporter (LT-SBP) in lactulose metabolism and its putative role in enriching the gut microbiota with bifidobacteria that encode this transporter. Their results might help in predicting prebiotics-responder and nonresponder status, helping the clinical interventions testing the efficacy of prebiotics.

Abstract Aim Recent studies have suggested that oral bacteria induce systemic inflammation through the alteration of gut microbiota. We examined the relationship between oral and gut microbiota to evaluate the transition of oral bacteria to the gastrointestinal tract. Methods Oral samples from subgingival plaque and tongue‐coating and fecal samples were collected from 29 elderly subjects (age, 80.2 ± 9.1 years) and 30 adults (age, 35.9 ± 5.0 years). Genomic DNA was extracted from all samples, and DNA sequencing of bacterial 16S rRNA genes was performed for microbiota analysis. UniFrac distances were calculated to evaluate the similarity between microbial communities. Results Unweighted UniFrac distance indicated that the elderly group had a higher similarity between fecal and subgingival plaque microbiota than the adult group. Indeed, some bacterial taxa found in oral samples had a significantly higher prevalence in the feces of the elderly group than in that of the adult group. Conclusions The prevalence of oral bacterial transition to gut may be higher in the elderly than in adults, expecting that oral health care in the elderly will affect their gut microbiota composition and consequently promote human health.

Probiotics have shown great promise in promoting human health. Despite the promising evidence, there is little information on the clinical efficacy of many of the available probiotics and their mechanisms of action are often unclear. Bifidobacterium longum subsp. longum BB536 is a clinically effective, well-established, multifunctional probiotic that has a long history of human use in alleviating gastrointestinal, immunological and infectious diseases. This review summarizes the functional benefits of BB536 from the most relevant clinical and animal studies and offers a theoretical basis for understanding its mechanisms of action. Key clinical findings point out that BB536 could act as a microbiome modulator to orchestrate the physiological activities of gut communities. Specifically, BB536 modulates luminal metabolism, stabilizes gut microbiota, and ultimately drives a fine-tuned homeostatic balance within the host-microbiome interaction. Clinical evidence of effectiveness of BB536 and how such multifunctional activities take place would be valuable for an optimized probiotic selection.

The colonization and persistence of probiotics introduced into the adult human gut appears to be limited. It is uncertain, however, whether probiotics can successfully colonize the intestinal tracts of full-term and premature infants. In this study, we investigated the colonization and the effect of oral supplementation with Bifidobacterium breve M-16V on the gut microbiota of low birth weight (LBW) infants. A total of 22 LBW infants (12 infants in the M-16V group and 10 infants in the control group) were enrolled. B. breve M-16V was administrated to LBW infants in the M-16V group from birth until hospital discharge. Fecal samples were collected from each subject at weeks (3.7–9.3 weeks in the M-16V group and 2.1–6.1 weeks in the control group) after discharge. qPCR analysis showed that the administrated strain was detected in 83.3% of fecal samples in the M-16V group (at log10 8.33 ± 0.99 cell numbers per gram of wet feces), suggesting that this strain colonized most of the infants beyond several weeks post-administration. Fecal microbiota analysis by 16S rRNA gene sequencing showed that the abundance of Actinobacteria was significantly higher (P < 0.01), whereas that of Proteobacteria was significantly lower (P < 0.001) in the M-16V group as compared with the control group. Notably, the levels of the administrated strain and indigenous Bifidobacterium bacteria were both significantly higher in the M-16V group than in the control group. Our findings suggest that oral administration of B. breve M-16V led to engraftment for at least several weeks post-administration and we observed a potential overall improvement in microbiota formation in the LBW infants’ guts.

We previously investigated the gut microbiota of 453 healthy Japanese subjects aged 0 to 104 years and found that the composition of the gut microbiota could be classified into some age-related clusters. In this study, we compared fecal metabolites between age-matched and age-mismatched elderly subjects to examine the roles of the gut microbiota in the health of the elderly. Fecal metabolites in 16 elderly subjects who fell into an age-matched cluster (elderly-type gut microbiota group, E-GM) and another 16 elderly subjects who fell into an age-mismatched cluster (adult-type gut microbiota group, A-GM) were measured by CE-TOF-MS. A total of eight metabolites were significantly different between the groups: cholic acid and taurocholic acid were enriched in the A-GM group, whereas choline, trimethylamine (TMA), N8-acetylspermidine, propionic acid, 2-hydroxy-4-methylvaleric acid, and 5-methylcytosine were enriched in the E-GM group. Some metabolites (choline, TMA, N8-acetylspermidine) elevated in the E-GM group were metabolites or precursors reported as risk factors for age-associated diseases such as arteriosclerosis and colorectal cancer. The abundance of some species belongs to Proteobacteria, which were known as TMA-producing bacteria, was increased in the E-GM group and correlated with fecal TMA levels. In vitro assays showed that these elderly-type fecal metabolites suppressed the expression of genes related to tight junctions in normal colonic epithelial cells and induced the expression of inflammatory cytokines in colon cancer cells. These findings suggest that metabolites produced by the aged gut microbiota could contribute to intestinal and systemic homeostasis and could be targeted for preventing aging-associated diseases.

The gut microbiome is a dynamic community that significantly affects host health; it is frequently disturbed by medications such as antibiotics. Recently, probiotics have been proposed as a remedy for antibiotic-induced dysbiosis, but the efficacy of such treatments remains uncertain. Thus, the effect of specific antibiotic-probiotic combinations on the gut microbiome and host health warrants further research. We tested the effect vancomycin, amoxicillin, and ciprofloxacin on mice. Antibiotic administration was followed by one of the following recovery treatments: Bifidobacterium bifidum JCM 1254 as a probiotic (PR); fecal transplant (FT); or natural recovery (NR). Each antibiotic administration and recovery treatment was repeated three times over 9 weeks. We used the Shannon Index and Chao1 Index to determine gut microbiome diversity and assessed recovery by quantifying the magnitude of microbial shift using the Bray-Curtis Index of Dissimilarity. We determined the community composition by sequencing the V3–V4 regions of the 16S ribosomal RNA gene. To assess host health, we measured body weight and cecum weight, as well as mRNA expression of inflammation-related genes by reverse-transcription quantitative PCR. Our results show that community response varied by the type of antibiotic used, with vancomycin having the most significant effects. As a result, the effect of probiotics and fecal transplants also varied by antibiotic type. For vancomycin, the first antibiotic disturbance substantially increased the relative abundance of inflammatory species in the phylum Proteobacteria, such as Proteus, but the effect of subsequent disturbances was less pronounced, suggesting that the gut microbiome is affected by past disturbance events. Furthermore, although gut microbiome diversity did not recover, probiotic supplementation was effective in limiting cecum size enlargement and colonic inflammation caused by vancomycin. However, for amoxicillin and ciprofloxacin, the relative abundances of proinflammatory species were not greatly affected, and consequently, the effect of probiotic supplementation on community structure, cecum weight, and expression of inflammation-related genes was comparatively negligible. These results indicate that probiotic supplementation is effective, but only when antibiotics cause proinflammatory species-induced gut inflammation, suggesting that the necessity of probiotic supplementation is strongly influenced by the type of disturbance introduced to the community.

الملخص: أهداف البحث: الأطفال عرضة للأمراض المعدية التي تأتي من أقرانهم في الحضانات، ورياض الأطفال، ومراكز الرعاية النهارية. بينت بعض الدراسات أن تناول الكائنات الدقيقة النافعة يقلل من عدد الإصابات بتلك الأمراض، الأمر الذي يؤدي إلى التقليل من الغياب ومن تناول المضادات الحيوية. مع التوجه للتركيز الأقل على والتفضيل الأقل لأخذ عينات الدم من الصغار، فإن الكثير من البيانات القابلة للقياس الكمي يتم الحصول عليها فقط من الدراسات الاستقصائية والاستبيانات. يبلغ ٢٥٪ من سكان ماليزيا من أصل صيني. استهدفنا تطوير أداة واحدة يمكن من خلالها إجراء تقييمات متزامنة لأمراض ذات صلة بالجهازين الهضمي والتنفسي لدى الأطفال الصينيين الصغار. طرق البحث: تمت ترجمة الاستبانات المصادق عليها باللغة الإنجليزية، التي تشمل بيانات متعلقة بالديموغرافيا والسجلات الصحية الشهرية إلى اللغة الصينية. وتمت المصادقة على نسختي الترجمة؛ من الصينيية إلى الإنجليزية ومن الإنجليزية إلى الصينية. النتائج: أظهرت الاستبانات الديموغرافية والشهرية الصحية، مؤشري صلاحية مستوى كلي للبند مستواهما ٠.٩٩و ٠.٩٧على التوالي، بينما أظهرت النسخ الصينية المترجمة مؤشري صلاحية مستوى كلي للبند مستواهما ٠.٩٧ و٠.٩٨على التوالي. كما تم الحصول على مؤشر صلاحية عملية الاستجابة للبند بمستوى ١.٠٠ لهذه الاستبانة من ٣٠ من المجيبين مما يدل على أن البنود كانت واضحة ومفهومة. الاستنتاجات: أظهرت هذه الدراسة مستوى جيدا من مؤشر الصلاحية في النسخة المترجمة الصينية، مما يدل على أنها أداة صالحة وموثوق بها لاستخدامها في التقييم المتزامن للأمراض ذات الصلة بالجهازين الهضمي والتنفسي في الأطفال الصغار ويمكن تطبيقها على سكان ماليزيا الصينيين والدول الأخرى الناطقة بالصينية. Abstract: Objectives: Children are prone to contagious illnesses that come from peers in nurseries, kindergartens, and day care centres. The administration of probiotics has been reported to decrease the episodes of such illnesses, leading to decreased absences and consumption of antibiotics. With less emphasis on, and preferences for, blood collection from young subjects, quantifiable data are merely obtained from surveys and questionnaires. Malaysia has a population which is 25% ethnic Chinese. We aimed to develop a single tool that enables simultaneous assessments of both gastrointestinal and respiratory tract-related illnesses among young Chinese children. Methods: The English-language validated questionnaires using data about demographics and monthly health records were translated into the Chinese language. Both forward and backward translated versions were validated. Results: The developed demographic and monthly health questionnaires showed an overall item-level content validity index (I-CVI) of 0.99 and 0.97, respectively; while the translated Chinese versions showed I-CVI of 0.97 and 0.98, respectively. Item-level of response process validity index of 1.00 for this questionnaire was obtained from 30 respondents inferring that the items were clear and comprehensible. Conclusions: This study showed acceptable levels validity in the Chinese translated version, illustrating a valid and reliable tool to be used for simultaneous assessment of gastrointestinal and respiratory tract-related illnesses in young children that is applicable for Malaysia's Chinese population and other Chinese-speaking nations. الكلمات المفتاحية: التنمية؛ إسهال, الاستبانة, الأمراض ذات الصلة بالجهاز التنفسي, التحقق من الصحة, Keywords: Development, Diarrhoea, Questionnaire, Respiratory tract-related illnesses, Validation

Hydroxycarboxylic acid receptor 3 (HCA3) was recently identified in the genomes of humans and other hominids but not in other mammals. We examined the production of HCA3 ligands by Bifidobacterium spp. In addition to 4-hydroxyphenyllactic acid, phenyllactic acid (PLA), and indole-3-lactic acid (ILA), we found that LeuA was produced by Bifidobacterium as an HCA3 ligand. The four ligands produced were the mixtures of enantiomers, and D-ILA, D-PLA, and D-LeuA showed stronger activity of the HCA3 ligand than their respective L-isomers. However, there was no difference in AhR activity between the two ILA enantiomers. These results provide new insights into the HCA3 ligands produced by Bifidobacterium and suggest the importance of investigating the absolute stereo structures of these metabolites.

Recent studies have suggested an association between certain members of the Fusobacterium genus, especially F. nucleatum, and the progression of advanced colorectal carcinoma (CRC). We assessed such an association of the gut microbiota in Japanese patients with colorectal adenoma (CRA) or intramucosal CRC using colonoscopy aspirates. We analyzed samples from 81 Japanese patients, including 47 CRA and 24 intramucosal CRC patients, and 10 healthy subjects. Metagenomic analysis of the V3-V4 region of the 16S ribosomal RNA gene was performed. The linear discriminant analysis (LDA) effect size (LEfSe) method was used to examine microbial dysbiosis, revealing significant differences in bacterial abundances between the healthy controls and CRA or intramucosal CRC patients. In particular, F. varium was statistically more abundant in patients with CRA and intramucosal CRC than in healthy subjects. Here, we present the metagenomic profile of CRA and intramucosal CRC and demonstrate that F. varium is at least partially involved in the pathogenesis of CRA and intramucosal CRC.

Gut microbiota-derived tryptophan metabolites such as indole derivatives are an integral part of host metabolome that could mediate gut−brain communication and contribute to host homeostasis. We previously reported that infant-type Human-Residential Bifidobacteria (HRB) produced higher levels of indole-3-lactic acid (ILA), suggesting the former might play a specific role in microbiota−host crosstalk by producing ILA in human infants. Nonetheless, the biological meaning of bifidobacteria-derived ILA in infant health development remains obscure. Here, we sought to explore the potential role of ILA in neuronal differentiation. We examined the neurite outgrowth and acetylcholinesterase (AchE) activity of PC12 cells following exposure to ILA and NGF induction. We found that ILA substantially enhanced NGF-induced neurite outgrowth of PC12 cells in a dose-dependent manner, and had the most prominent effect at 100 nM. Significant increases in the expression of TrkA receptor, ERK1/2 and CREB were observed in ILA-treated PC12 cells, suggesting ILA potentiated NGF-induced neurite outgrowth through the Ras/ERK pathway. Additionally, ILA was found to act as the aryl hydrocarbon receptor (AhR) agonist and evoked NGF-induced neurite outgrowth in an AhR-mediated manner. These new findings provide clues into the potential involvement of ILA as the mediator in bifidobacterial host−microbiota crosstalk and neuronal developmental processes.

Antigen-specific immunoglobulin (Ig) A plays a major role in host defense against infections in gut mucosal tissue. Follicular helper T (Tfh) cells are located in germinal centers and promote IgA production via interactions with germinal center B cells. Several studies have demonstrated that some lactic acid bacteria (LAB) strains activate the host's acquired immune system, inducing IgA secretion in the intestine. However, the precise molecular mechanisms underlying the effects of LAB on IgA production and Tfh cells are not fully resolved. Lactobacillus paracasei MCC1849 is a probiotic strain isolated from the intestine of a healthy adult. In this study, we investigated the effects of orally administered heat-killed MCC1849 on IgA production in the intestine and on Tfh cell induction in vivo. We found that orally administered MCC1849 induced antigen-specific IgA production in the small intestine, serum and lungs. We also observed that MCC1849 increased the proportion of IgA+ B cells and Tfh cells in Peyer's patches (PPs). In addition, MCC1849 increased the gene expression of IL-12p40, IL-10, IL-21, STAT4 and Bcl-6 associated with Tfh cell differentiation. These results suggest that orally administered MCC1849 enhances antigen-specific IgA production and likely affects Tfh cell differentiation in PPs.

Previous studies have shown that Japanese people exhibit a higher abundance of Bifidobacterium compared to people from other countries. Among the possible factors affecting the gut microbiota composition, an association of functional lactase gene variants with a higher abundance of Bifidobacterium in the gut has been proposed in some reports. However, no Japanese subjects were included in these studies. In this study, we investigated the possible contribution of functional lactase loci to the high abundance of Bifidobacterium in Japanese populations. Based on a data analysis assessing 1,068 healthy Japanese adults, a number of subjects is at least seven times greater than that reported in available online data. all subjects possessed CC genotype at rs4988235 and the GG at rs182549, which are associated with low lactase activity. We observed a positive correlation between dairy product intake and Bifidobacterium abundance in the gut. Considering previous reports, which revealed that four additional functional lactase loci, rs145946881, rs41380347, rs41525747 and rs869051967 (ss820486563), are also associated with low lactase activity in Japanese people, our findings imply the possible contribution of host genetic variation-associated low lactase activity to the high abundance of Bifidobacterium in the Japanese population.

Gut microbiota is known to change with aging; however, the underlying mechanisms have not been well elucidated. Immunoglobulin A (IgA) is the dominant class of antibody secreted by the intestinal mucosa, and are thought to play a key role in the regulation of the gut microbiota. T cells regulate the magnitude and nature of microbiota-specific IgA responses. However, it is also known that T cells become senescent in elderly people. Therefore, we speculated that the age-related changes of IgA response against the gut microbiota might be one of the mechanisms causing the age-associated changes of gut microbiota composition. To prove our hypothesis, fecal samples from 40 healthy subjects (adult group: n = 20, an average of 35 years old; elderly group: n = 20, an average of 76 years old) were collected, and the gut microbiota composition and the response of IgA to gut microbiota were investigated. The relative abundance of Bifidobacteriaceae was significantly lower, whereas those of Clostridiaceae, Clostridiales;f__ and Enterobacteriaceae were significantly higher in the elderly group than in the adult group. There was no significant difference in the fecal IgA concentration between the adult and elderly groups. However, the taxon-specific IgA response to some bacterial taxa was different between the adult and elderly groups. To evaluate inter-group differences in the taxon-specific IgA response to each bacterial taxon, the IgA-indices were calculated, and the IgA-indices of Clostridiaceae and Enterobacteriaceae were found to be significantly lower in the elderly group than the adult group. In addition, Clostridiales;f__ and Enterobacteriaceae were significantly enriched in the IgA+ fraction in the adult group but not in the elderly group, whereas Clostridiaceae was significantly enriched in the IgA- fraction in the elderly group but not in the adult group. Some species assigned to Clostridiaceae or Enterobacteriaceae are known to be pathogenic bacteria. Our results suggest the possible contribution of decreased IgA response in the increased abundance of bacterial taxa with potential pathogenicity in the intestinal environment of the elderly. Our findings contribute to the understanding of the regulatory factor for the changes in the gut microbiota composition with aging.

There is a growing interest in identifying natural food ingredients that may serve to prevent dementia such as that due to Alzheimer disease (AD). Peptides derived from food proteins have been demonstrated to have various physiological activities such as a hypotensive action. Recent findings have indicated possible associations of hypertension with AD progression, and suggest that angiotensin converting enzyme (ACE) inhibitors with potential to pass through the blood brain barrier (BBB) may reduce the risk of AD. In this study, we investigated the effect of milk peptide (CH-3) on cognitive function in AD model mice. CH-3 contains a tripeptide (methionine-lysine-proline, MKP) that has been found to have a strong ACE inhibitory effect and the potential to pass through the BBB. Adult male ddY mice were used in this study, and an animal model of AD was induced by intracerebroventricular (ICV) injection of Aβ1-42. CH-3 (250 mg/kg/day) or MKP (0.5 mg/kg/day) was orally administered every day starting 2 days before ICV injection. At 3 weeks after ICV injection, cognitive function was evaluated by the Morris water maze test. Brain samples were obtained after behavioral testing, and expression of inflammatory cytokines and NADPH oxidase subunits was measured by real-time quantitative RT-PCR. ICV injection of Aβ1-42 significantly impaired cognitive function compared with that in PBS-injected mice. Daily administration of CH-3 markedly attenuated this Aβ1-42-induced cognitive decline. Aβ1-42 injection significantly enhanced the expression of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and p22phox in the mouse hippocampus compared with PBS injection, and showed a tendency to increase the expression of monocyte chemoattractant protein-1 (MCP-1), p47phox and gp91phox, whereas CH-3 treatment markedly reduced Aβ1-42-induced TNF-α, MCP-1, iNOS, p47phox and gp91phox expression. Finally, administration of MKP also attenuated Aβ1-42-induced cognitive impairment with an increase in cerebral blood flow. The present study demonstrated that repeated oral administration of CH-3 to AD model mice not only improved cognitive function but also suppressed the expression of inflammatory cytokines and production of oxidative stress, and suggests its therapeutic potential for preventing cognitive impairment in AD.

Background: Probiotic administration may be a useful method for preventing allergies in infants; however, there have been controversial results about the efficacy. We investigated the effects of bifidobacterial supplementation on the risk of developing allergic diseases in the Japanese population. Methods: In an open trial, we gave Bifidobacterium breve M-16V and Bifidobacterium longum BB536 prenatally to 130 mothers beginning 1 month prior to delivery and postnatally to their infants for 6 months. Another 36 mother-infant pairs served as controls and did not receive the bifidobacterial supplementation. Development of allergic symptoms in the infants was assessed at 4, 10 and 18 months of age. Fecal samples were collected from the mothers and infants. Results: The risk of developing eczema_atopic dermatitis (AD) during the first 18 months of life was significantly reduced in infants in the probiotic group (OR: 0.231 [95% CI: 0.084-0.628] and 0.304 [0.105-0.892] at 10 and 18 months of age, respectively). Pyrosequencing analyses indicated an altered composition of the fecal microbiota at 4 months for infants who developed eczema_AD at 4 and 10 months of age. The proportion of Proteobacteria was significantly lower (P = 0.007) in mothers at the time of delivery who received the supplementation when compared with the control group and was positively correlated (r = 0.283, P = 0.024) with that of infants at 4 months of age. No adverse effects were related to the use of probiotics. Conclusions: These data suggest that the prenatal and postnatal supplementation of bifidobacteria is effective in primary preventing allergic diseases. Some limited changes in the composition of fecal microbiota by the bifidobacterial supplementation were observed.

Recent studies have shown that metabolites produced by microbes can be considered as mediators of host-microbial interactions. In this study, we examined the production of tryptophan metabolites by Bifidobacterium strains found in the gastrointestinal tracts of humans and other animals. Indole-3-lactic acid (ILA) was the only tryptophan metabolite produced in bifidobacteria culture supernatants. No others, including indole-3-propionic acid, indole-3-acetic acid, and indole-3-aldehyde, were produced. Strains of bifidobacterial species commonly isolated from the intestines of human infants, such as Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium breve, and Bifidobacterium bifidum, produced higher levels of ILA than did strains of other species. These results imply that infant-type bifidobacteria might play a specific role in host−microbial cross-talk by producing ILA in human infants.

Peptidoglycan recognition proteins (PGLYRPs) are a family of pattern recognition receptors (PRRs) that are able to induce innate immune responses through their binding to peptidoglycan (PGN), lipopolysaccharide, or lipoteichoic acid, or by interacting with other PRR-ligands. Recently, progress has been made in understanding the immunobiology of PGLYRPs in human and mice, however, their functions in livestock animals have been less explored. In this study, we characterized the expression patterns of PGLYRPs in porcine intestinal epithelial (PIE) cells and antigen-presenting cells (APCs) and their modulation by the interactions of host cells with PRR-ligands and non-viable immunomodulatory probiotics referred to as paraimmunobiotics. We demonstrated that PGLYRP-1, -2, -3, and -4 are expressed in PIE cells and APCs from Peyer’s patches, being PGLYPR-3 and -4 levels higher than PGLYRP-1 and -2. We also showed that PGLYRPs expression in APCs and PIE cells can be modulated by different PRR agonists. By using knockdown PIE cells for TLR2, TLR4, NOD1, and NOD2, or the four PGLYRPs, we demonstrated that PGLYRPs expressions would be required for activation and functioning of TLR2, TLR4, NOD1, and NOD2 in porcine epitheliocytes, but PGLYRPs activation would be independent of those PRR expressions. Importantly, we reported for the first time that PGLYRPs expression can be differentially modulated by paraimmunobiotic bifidobacteria in a strain-dependent manner. These results provide evidence for the use of paraimmunobiotic bifidobacteria as an alternative for the improvement of resistance to intestinal infections or as therapeutic tools for the reduction of the severity of inflammatory damage in diseases in which a role of PGLYRPs-microbe interaction has been demonstrated.

In this work, we aimed to characterize the antiviral response of an originally established porcine intestinal epithelial cell line (PIE cells) by evaluating the molecular innate immune response to rotavirus (RVs). In addition, we aimed to select immunomodulatory bacteria with antiviral capabilities. PIE cells were inoculated with RVs isolated from different host species and the infective titers and the molecular innate immune response were evaluated. In addition, the protection against RVs infection and the modulation of immune response by different lactic acid bacteria (LAB) strains was studied. The RVs strains OSU (porcine) and UK (bovine) effectively infected PIE cells. Our results also showed that RVs infection in PIE cells triggered TLR3-, RIG-I- and MDA-5-mediated immune responses with activation of IRF3 and NF-κB, induction of IFN-β and up-regulation of the interferon stimulated genes MxA and RNase L. Among the LAB strains tested, Bifidobacterium infantis MCC12 and B. breve MCC1274 significantly reduced RVs titers in infected PIE cells. The beneficial effects of both bifidobacteria were associated with reduction of A20 expression, and improvements of IRF-3 activation, IFN-β production, and MxA and RNase L expressions. These results indicate the value of PIE cells for studying RVs molecular innate immune response in pigs and for the selection of beneficial bacteria with antiviral capabilities.

Accumulating evidence suggests an association between gut microbiota and the development of obesity, raising the possibility of probiotic administration as a therapeutic approach. Bifidobacterium breve B-3 was found to exhibit an anti-obesity effect on high-fat diet-induced obesity mice. In the present study, a randomised, double-blind, placebo-controlled trial was conducted to evaluate the effect of the consumption of B. breve B-3 on body compositions and blood parameters in adults with a tendency for obesity. After a 4-week run-in period, the participants were randomised to receive either placebo or a B-3 capsule (approximately 5 × 1010 colony-forming units of B-3/d) daily for 12 weeks. A significantly lowered fat mass was observed in the B-3 group compared with the placebo group at week 12. Improvements were observed for some blood parameters related to liver functions and inflammation, such as γ-glutamyltranspeptidase and high-sensitivity C-reactive protein. Significant correlations were found between the changed values of some blood parameters and the changed fat mass in the B-3 group. These results suggest the beneficial potential of B. breve B-3 in improving metabolic disorders.

Strains of Bifidobacterium longum, Bifidobacterium breve, and Bifidobacterium animalis are widely used as probiotics in the food industry. Although numerous studies have revealed the properties and functionality of these strains, it is uncertain whether these characteristics are species common or strain specific. To address this issue, we performed a comparative genomic analysis of 49 strains belonging to these three bifidobacterial species to describe their genetic diversity and to evaluate species-level differences. There were 166 common clusters between strains of B. breve and B. longum, whereas there were nine common clusters between strains of B. animalis and B. longum and four common clusters between strains of B. animalis and B. breve. Further analysis focused on carbohydrate metabolism revealed the existence of certain strain-dependent genes, such as those encoding enzymes for host glycan utilisation or certain membrane transporters, and many genes commonly distributed at the species level, as was previously reported in studies with limited strains. As B. longum and B. breve are human-residential bifidobacteria (HRB), whereas B. animalis is a non-HRB species, several of the differences in these species’ gene distributions might be the result of their adaptations to the nutrient environment. This information may aid both in selecting probiotic candidates and in understanding their potential function as probiotics.

BACKGROUND: We previously showed that evaluation of anti-inflammatory activities of lactic acid bacteria in porcine intestinal epithelial (PIE) cells is useful for selecting potentially immunobiotic strains. OBJECTIVE: The aims of the present study were: i) to select potentially immunomodulatory bifidobacteria that beneficially modulate the Toll-like receptor (TLR)-4-triggered inflammatory response in PIE cells and; ii) to gain insight into the molecular mechanisms involved in the anti-inflammatory effect of immunobiotics by evaluating the role of TLR2 and TLR negative regulators in the modulation of proinflammatory cytokine production and activation of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways in PIE cells. RESULTS: Bifidobacteria longum BB536 and B. breve M-16V strains significantly downregulated levels of interleukin (IL)-8, monocyte chemotactic protein (MCP)-1 and IL-6 in PIE cells challenged with heat-killed enterotoxigenic Escherichia coli. Moreover, BB536 and M-16V strains attenuated the proinflammatory response by modulating the NF-κB and MAPK pathways. In addition, our findings provide evidence for a key role for the ubiquitin-editing enzyme A20 in the anti-inflammatory effect of immunobiotic bifidobacteria in PIE cells. CONCLUSIONS: We show new data regarding the mechanism involved in the anti-inflammatory effect of immunobiotics. Several strains with immunoregulatory capabilities used a common mechanism to induce tolerance in PIE cells. Immunoregulatory strains interacted with TLR2, upregulated the expression of A20 in PIE cells, and beneficially modulated the subsequent TLR4 activation by reducing the activation of MAPK and NF-κB pathways and the production of proinflammatory cytokines. We also show that the combination of TLR2 activation and A20 induction can be used as biomarkers to screen and select potential immunoregulatory bifidobacteria strains.