Lactic acid bacteria inducing a weak interleukin-12 and tumor necrosis factor alpha response in human dendritic cells inhibit strongly stimulating lactic acid bacteria but act synergistically with gram-negative bacteria

Bacterial distribution and inflammatory cytokines associated with oral cancer with and without jawbone invasion-a pilot study

OBJECTIVE

To explore the bacterial and inflammatory variations in oral cancer patients with and without jawbone invasion.

MATERIALS AND METHODS

A total of 20 specimens of fresh tumor tissue, including 10 from the tumor-invaded jawbone (JIOC group) and 10 without jawbone invasion (NJIOC group), were collected from oral cancer patients. Meanwhile, 10 specimens from normal oral mucosa were collected from healthy patients (control group). The microbiomic content of each sample was analyzed by 16S rRNA gene sequencing, while the expression of inflammatory cytokines was assessed using protein microarray analysis.

RESULTS

There was a significant difference in β diversity between JIOC and NJIOC groups (P < 0.05), but no difference between NJIOC and control groups. The average relative abundance of Fusobacteria and Spirochaetes was higher, while Firmicutes was lower in the JIOC group than in the NJIOC group (all P < 0.05). The expression of pro-inflammatory cytokines like interleukin (IL)-1α, IL-1β, IL-4, and IL-8 was upregulated in the JIOC group compared with the NJIOC group, while MCP-1 was decreased (all P < 0.05). Slackia spp. and Howardella spp. were positively correlated with IL-4; Odoribacter spp. and Acidaminococcaceae spp. were negatively correlated with IL-4, and Clostridium XIVa spp. was negatively correlated with IL-1α and IL-1β.

CONCLUSION

Bacterial and inflammatory differences were observed in oral cancer patients with and without jawbone invasion, where the relative abundance of the differential bacteria was associated with the expression of the inflammatory cytokines.

CLINICAL RELEVANCE

This study investigated the changes in the flora during jawbone invasion in oral cancer and its effect on inflammatory factors, elucidating the possible mechanisms of jawbone invasion caused by oral cancer, which may lead to new ideas for the clinical prevention and treatment of jawbone invasion in oral cancer.

Investigation of the Effects of Monomeric and Dimeric Stilbenoids on Bacteria-Induced Cytokines and LPS-Induced ROS Formation in Bone Marrow-Derived Dendritic Cells

Stilbenoids are anti-inflammatory and antioxidant compounds, with resveratrol being the most investigated molecule in this class. However, the actions of most other stilbenoids are much less studied. This study compares five monomeric (resveratrol, piceatannol, pterostilbene, pinostilbene, and trimethoxy-resveratrol) and two dimeric (dehydro-δ-viniferin and trans-δ-viniferin) stilbenoids for their capability to modulate the production of bacteria-induced cytokines (IL-12, IL-10, and TNF-α), as well as lipopolysaccharide (LPS)-induced reactive oxygen species (ROS), in murine bone marrow-derived dendritic cells. All monomeric species showed dose-dependent inhibition of E. coli-induced IL-12 and TNF-α, whereas only resveratrol and piceatannol inhibited IL-10 production. All monomers, except trimethoxy-resveratrol, inhibited L. acidophilus-induced IL-12, IL-10, and TNF-α production. The dimer dehydro-δ-viniferin remarkably enhanced L. acidophilus-induced IL-12 production. The contrasting effect of resveratrol and dehydro-δ-viniferin on IL-12 production was due, at least in part, to a divergent inactivation of the mitogen-activated protein kinases by the two stilbenoids. Despite having moderate to high total antioxidant activity, dehydro-δ-viniferin was a weak inhibitor of LPS-induced ROS formation. Conversely, resveratrol and piceatannol potently inhibited LPS-induced ROS formation. Methylated monomers showed a decreased antioxidant capacity compared to resveratrol, also depending on the methylation site. In summary, the immune-modulating effect of the stilbenoids depends on both specific structural features of tested compounds and the stimulating bacteria.

Probiotic immunonutrition impacts on colon cancer immunotherapy and prevention

The important role of the immune system in treating cancer has attracted the attention of researchers to the emergence of oncology research. Immunotherapy has shown that the immune system is important in the fight against cancer. The challenge has led researchers to analyze the impact of immunotherapy on improving the status of the immune system, modifying the resulting safety response, reducing toxicity, and improving the results. This study aimed to discuss the potential mechanisms of probiotics in preventing colon cancer. The mechanisms include the change in intestinal microbiota, the metabolic activity of microbiota, the binding and degradation of the carcinogenic compounds present in the lumen of the intestine, the production of compounds with anticancer activity, immune system modification, intestinal dysfunction, changes in host physiology, and inhibition of cell proliferation and induction of apoptosis in cancerous cells. By contrast, very few reports have shown the harmful effects of oral probiotic supplements. According to available evidence, further studies on probiotics are needed, especially in identifying bacterial species with anticancer potential, studying the survival of the strains after passing the digestive tract, reviewing potential side effects in people with a weak immune system, and ultimately consuming and repeating its use. This study emphasizes that the nutritional formula can modulate inflammatory and immune responses in cancer patients. This effect reduces acute toxicity, although the pathways and measurement of this immune response are unclear. Nutrition safety is an emerging field in oncology, and further research is required.

Gut Microbiota Composition in Prediabetes and Newly Diagnosed Type 2 Diabetes: A Systematic Review of Observational Studies

Evidence of gut microbiota involvement in regulating glucose metabolism and type 2 diabetes mellitus (T2DM) progression is accumulating. The understanding of microbial dysbiosis and specific alterations of gut microbiota composition that occur during the early stages of glucose intolerance, unperturbed by anti-diabetic medications, is especially essential. Hence, this systematic review was conducted to summarise the existing evidence related to microbiota composition and diversity in individuals with prediabetes (preDM) and individuals newly diagnosed with T2DM (newDM) in comparison to individuals with normal glucose tolerance (nonDM). A systematic search of the PubMed, MEDLINE and CINAHL databases were conducted from inception to February 2021 supplemented with manual searches of the list of references. The primary keywords of “type 2 diabetes”, “prediabetes”, “newly-diagnosed” and “gut microbiota” were used. Observational studies that conducted analysis of the gut microbiota of respondents with preDM and newDM were included. The quality of the studies was assessed using the modified Newcastle-Ottawa scale by independent reviewers. A total of 18 studies (5,489 participants) were included. Low gut microbial diversity was generally observed in preDM and newDM when compared to nonDM. Differences in gut microbiota composition between the disease groups and nonDM were inconsistent across the included studies. Four out of the 18 studies found increased abundance of phylum Firmicutes along with decreased abundance of Bacteroidetes in newDM. At the genus/species levels, decreased abundance of Faecalibacterium prausnitzii, Roseburia, Dialister, Flavonifractor, Alistipes, Haemophilus and Akkermansia muciniphila and increased abundance of Lactobacillus, Streptococcus, Escherichia, Veillonella and Collinsella were observed in the disease groups in at least two studies. Lactobacillus was also found to positively correlate with fasting plasma glucose (FPG), HbA1c and/or homeostatic assessment of insulin resistance (HOMA-IR) in four studies. This renders a need for further investigations on the species/strain-specific role of endogenously present Lactobacillus in glucose regulation mechanism and T2DM disease progression. Differences in dietary intake caused significant variation in specific bacterial abundances. More studies are needed to establish more consistent associations, between clinical biomarkers or dietary intake and specific gut bacterial composition in prediabetes and early T2DM.

Evidence Suggesting the Role of Gut Dysbiosis in Diabetic Retinopathy

Purpose

Gut dysbiosis has been identified and tested in human trials for its role in diabetes mellitus (DM). The gut-retina axis could be a potential target for retardation of diabetic retinopathy (DR), a known complication of DM. This study reviews the evidence suggesting gut dysbiosis in DR.

Methods

The published literature in the past 5 years was reviewed using predetermined keywords and articles. The review intended to determine changes in gut microbiome in DR, the hypothesized mechanisms linking to the gut-retina axis, its predictive potential for progression of DR, and the possible therapeutic targets.

Results

The gut microbiota of people with DM differ from those without it, and the gut microbiota of people with DR differ from those without it. The difference is more significant in the former (DM versus no DM) and less significant in the latter (DM without DR versus DM with DR). Early research has suggested mechanisms of the gut-retina axis, but these are not different from known changes in the gut microbiome of people with DM. The current evidence on the predictive value of the gut microbiome in the occurrence and progression of DR is low. Therapeutic avenues targeting the gut-retina axis include lifestyle changes, pharmacologic inhibitors, probiotics, and fecal microbiota transplantation.

Conclusions

Investigating the therapeutic utility of the gut ecosystem for DM and its complications like DR is an emerging area of research. The gut-retina axis could be a target for retardation of DR but needs longitudinal regional studies adjusting for dietary habits.

Differential effects of orally administered <i>Lactobacillus acidophilus</i> L-55 on the gene expression of cytokines and master immune switches in the ileum and spleen of laying hen with an attenuated Newcastle disease virus vaccine

This study aimed to evaluate the benefits of oral administration of Lactobacillus acidophilus strain L-55 (LaL-55) to chickens inoculated with a Newcastle disease virus (NDV)-based live-attenuated vaccine by examining the mRNA expression of several genes related to viral infection in the spleen and ileum by quantitative reverse transcription polymerase chain reaction. In the spleen, interferon (IFN)-α was significantly higher in the low- and middle-dose LaL-55 groups at 6 weeks than at 4 weeks. IFN regulatory factor (IRF)-3 and IRF-7 expression was significantly higher in the low-dose LaL-55 group than in the middle- and high-dose LaL-55 groups. In the ileum, melanoma differentiation-associated gene 5 showed a dose-dependent increase at 4 weeks. IFN-γ and IRF-7 showed dose-dependent increases at 6 weeks. These results suggested that LaL-55 boosts the immune response to the NDV vaccine, albeit by different mechanisms in the spleen and ileum.

Evaluation of the Function of Probiotics, Emphasizing the Role of their Binding to the Intestinal Epithelium in the Stability and their Effects on the Immune System

Due to the importance of using cost-effective methods for therapeutic purposes, the function of probiotics as safe microorganisms and the study of their relevant functional mechanisms have recently been in the spotlight. Finding the mechanisms of attachment and stability and their beneficial effects on the immune system can be useful in identifying and increasing the therapeutic effects of probiotics. In this review, the functional mechanisms of probiotics were comprehensively investigated. Relevant articles were searched in scientific sources, documents, and databases, including PubMed, NCBI, Bactibace, OptiBac, and Bagel4. The most important functional mechanisms of probiotics and their effects on strengthening the epithelial barrier, competitive inhibition of pathogenic microorganisms, production of antimicrobials, binding and interaction with the host, and regulatory effects on the immune system were discussed.

In this regard, the attachment of probiotics to the epithelium is very important because the prerequisite for their proper functioning is to establish a proper connection to the epithelium. Therefore, more attention should be paid to the binding effect of probiotics, including sortase A, a significant factor involved in the expression of sortase-dependent proteins (SDP), on their surface as mediators of intestinal epithelial cell binding. In general, by investigating the functional mechanisms of probiotics, it was concluded that the mechanism by which probiotics regulate the immune system and adhesion capacity can directly and indirectly have preventive and therapeutic effects on a wide range of diseases. However, further study of these mechanisms requires extensive research on various aspects.

Genomic Stability and Phenotypic Characteristics of Industrially Produced Lacticaseibacillus rhamnosus GG in a Yogurt Matrix

Lacticaseibacillus rhamnosus GG is a widely marketed probiotic with well-documented probiotic properties. Previously, deletion of the mucus-adhesive spaCBA-srtC1 genes in dairy isolates was reported. In this study, we examined the genome preservation of industrially produced L. rhamnosus GG (DSM 33156) cofermented in yogurts. In total, DNA of 66 samples, including 60 isolates, was sequenced. Population samples and 59 isolates exhibited an intact genome. One isolate exhibited loss of spaCBA-srtC1. In addition, we examined phenotypes related to the probiotic properties of L. rhamnosus GG either from frozen pellets or cofermented in yogurt. L. rhamnosus GG from frozen pellets induced a response in intestinal barrier function in vitro, in contrast to frozen pellets of the starter culture. Yogurt matrix, containing only the starter culture, induced a response, but cofermentation with L. rhamnosus GG induced a higher response. Conversely, only the starter culture stimulated cytokine secretion in dendritic cells, and it was observed that the addition of L. rhamnosus GG to the starter culture reduced the response. We conclude that the L. rhamnosus GG genome is preserved in yogurt and that common in vitro probiotic effects of L. rhamnosus GG are observed when examined in the yogurt matrix. IMPORTANCE Lacticaseibacillus rhamnosus GG is a well-documented probiotic strain recognized for its high acid and bile tolerance and properties of adhesion to enterocytes and mucus. The strain exhibits SpaCBA pili, which have been demonstrated to play an important role in adhesion and therefore are relevant for persistence in the gastrointestinal tract. Recently we demonstrated that the genome and phenotypes of L. rhamnosus GG are preserved throughout an industrial production pipeline. However, as gene deletions in L. rhamnosus GG were previously reported for isolates from dairy products, a key question on the genomic stability of L. rhamnosus GG in a yogurt matrix remained. The aim of this study was to analyze genome stability and phenotypic characteristics of L. rhamnosus GG in yogurt. We found that the genome of L. rhamnosus GG is well conserved when the organism is cofermented in yogurt. Some phenotypic characteristics are consistent in all product matrixes, while other characteristics are modulated.

Gut Bacterial Characteristics of Patients With Type 2 Diabetes Mellitus and the Application Potential

Type 2 diabetes mellitus (T2DM) is a complex disorder comprehensively influenced by genetic and environmental risk, and research increasingly has indicated the role of microbial dysbiosis in T2DM pathogenesis. However, studies comparing the microbiome characteristics between T2DM and healthy controls have reported inconsistent results. To further identify and describe the characteristics of the intestinal flora of T2DM patients, we performed a systematic review and meta-analysis of stool microbial profiles to discern and describe microbial dysbiosis in T2DM and to explore heterogeneity among 7 studies (600 T2DM cases, 543 controls, 1143 samples in total). Using a random effects model and a fixed effects model, we observed significant differences in beta diversity, but not alpha diversity, between individuals with T2DM and controls. We identified various operational taxonomic unit (OTUs) and bacterial genera with significant odds ratios for T2DM. The T2DM signatures derived from a single study by stepwise feature selection could be applied in other studies. By training on multiple studies, we improved the detection accuracy and disease specificity for T2DM. We also discuss the relationship between T2DM-enriched or T2DM-depleted genera and probiotics and provide new ideas for diabetes prevention and improvement.

Multi-Probiotic Lactobacillus Supplementation Improves Liver Function and Reduces Cholesterol Levels in Jeju Native Pigs

Simple Summary

Probiotics are used in the food industry as feed additives to maintain the balance of animal gut microbiota. They are also considered to have potential therapeutic effects against liver diseases. This study showed that dietary Lactobacillus supplementation improved liver function and reduced cholesterol levels in Jeju native pigs, with Toll-like receptors (TLR) signaling as the primary response in the gut against Lactobacillus and TNF-α/IFN-γ as the central mediator cytokines in the gut and liver tissues. Lactobacillus supplementation may be applied to treat metabolic disorders of the liver, especially cholesterol-related disorders, in farm animals.

Abstract

We evaluated the dietary effects of multiple probiotics in Jeju native pigs, using basal diet and multi-probiotic Lactobacillus (basal diet with 1% multi-probiotics) treatments (n = 9 each) for 3 months. We analyzed growth performance, feed efficiency, backfat thickness, blood parameters, hematological profiles, adipokines, and immune-related cytokines in pig tissues. Average daily gain, feed intake, feed efficiency, backfat thickness, and body weight were not significantly different between both groups. In Lactobacillus group, total protein (p < 0.08) and bilirubin (p < 0.03) concentrations increased; blood urea nitrogen (p < 0.08), alkaline phosphatase (p < 0.08), and gamma-glutamyltransferase (p < 0.08) activities decreased. Lactobacillus group showed decreased adiponectin (p < 0.05), chemerin (p < 0.05), and visfatin expression in adipose tissues, and increased TLR4 (p < 0.05), MYD88 (p < 0.05), TNF-α (p < 0.001), and IFN-γ (p < 0.001) expression in the liver. Additionally, NOD1 (p < 0.05), NOD2 (p < 0.01), and MYD88 (p < 0.05) mRNA levels in proximal colon tissue upregulated significantly. Colon, longissimus dorsi muscle, fat tissue, and liver histological analyses revealed no significant differences between the groups. Conclusively, Lactobacillus supplementation improved liver function and reduced cholesterol levels. Its application may treat metabolic liver disorders, especially cholesterol-related disorders.

Gut microbiome differences among Mexican Americans with and without type 2 diabetes mellitus

PURPOSE

Type 2 diabetes mellitus (T2DM) is an urgent public health problem and disproportionately affects Mexican Americans. The gut microbiome contributes to the pathophysiology of diabetes; however, no studies have examined this association in Mexican-Americans. The objective of this study was to compare gut microbiome composition between Mexican-Americans with and without T2DM.

METHODS

This was a cross-sectional study of volunteers from San Antonio, TX. Subjects were 18 years or older and self-identified as Mexican American. Subjects were grouped by prior T2DM diagnosis. Eligible subjects attended a clinic visit to provide demographic and medical information. Thereafter, subjects recorded their dietary intake for three days and collected a stool sample on the fourth day. Stool 16s rRNA sequences were classified into operational taxonomic units (OTUs) via the mothur bayesian classifier and referenced to the Greengenes database. Shannon diversity and bacterial taxa relative abundance were compared between groups using the Wilcoxon rank sum test. Beta diversity was estimated using Bray-Curtis indices and compared between groups using PERMANOVA.

RESULTS

Thirty-seven subjects were included, 14 (38%) with diabetes and 23 (62%) without diabetes. Groups were well-matched by body mass index and comorbid conditions. Shannon diversity was not significantly different between those with and without T2DM (3.26 vs. 3.31; p = 0.341). Beta diversity was not significantly associated with T2DM diagnosis (p = 0.201). The relative abundance of the most common bacterial phyla and families did not significantly differ between groups; however, 16 OTUs were significantly different between groups.

CONCLUSIONS

Although alpha diversity was not significantly different between diabetic and non-diabetic Mexican Americans, the abundance of certain bacterial taxa were significantly different between groups.

Tremella fuciformis Polysaccharides Inhibited Colonic Inflammation in Dextran Sulfate Sodium-Treated Mice via Foxp3+ T Cells, Gut Microbiota, and Bacterial Metabolites

Tremella fuciformis is an edible medicinal mushroom, and its polysaccharide components are found to confer various health benefits. This study identified the protective effects of polysaccharides of Tremella fuciformis (TPs) against dextran sulfate sodium (DSS)-induced colitis in mice. High dose of TPs (HTPs) could prevent the colon from shortening, reduce activity of colonic myeloperoxidase and serum diamine oxidase (DAO), decrease the concentration of D-lactate, and alleviate the colonic tissue damage in colitic mice. HTPs treatment stimulated Foxp3+T cells, and promoted the production of anti-inflammatory cytokines whereas it reduced the production of pro-inflammatory and the portion of immunoglobulin A (IgA)-coated bacteria, which was related to modulation of immune responses. 16S rRNA sequencing analysis showed that TPs could significantly increase gut community diversity, and restore the relative abundances of Lactobacillus, Odoribacter, Helicobacter, Ruminococcaceae, and Marinifilaceae. According to metabolomic analysis, HTPs induced specific microbial metabolites akin to that in normal mice. Tyrosine biosynthesis, tryptophan metabolism, and bile acid metabolism were influenced in the HTPs group compared with those in the DSS group. HTPs could alleviate DSS-induced colitis by immunoregulation and restored the gut microbiota and microbial metabolites. The results indicated that HTPs have potential to be developed as a food supplement to ameliorate intestinal diseases.

The Relationship between the Gut Microbiome and Metformin as a Key for Treating Type 2 Diabetes Mellitus

Metformin is the first-line pharmacotherapy for treating type 2 diabetes mellitus (T2DM); however, its mechanism of modulating glucose metabolism is elusive. Recent advances have identified the gut as a potential target of metformin. As patients with metabolic disorders exhibit dysbiosis, the gut microbiome has garnered interest as a potential target for metabolic disease. Henceforth, studies have focused on unraveling the relationship of metabolic disorders with the human gut microbiome. According to various metagenome studies, gut dysbiosis is evident in T2DM patients. Besides this, alterations in the gut microbiome were also observed in the metformin-treated T2DM patients compared to the non-treated T2DM patients. Thus, several studies on rodents have suggested potential mechanisms interacting with the gut microbiome, including regulation of glucose metabolism, an increase in short-chain fatty acids, strengthening intestinal permeability against lipopolysaccharides, modulating the immune response, and interaction with bile acids. Furthermore, human studies have demonstrated evidence substantiating the hypotheses based on rodent studies. This review discusses the current knowledge of how metformin modulates T2DM with respect to the gut microbiome and discusses the prospect of harnessing this mechanism in treating T2DM.

Dysbiosis and Implication of the Gut Microbiota in Diabetic Retinopathy

The pathogenesis of type 2 diabetes mellitus (T2DM) is commonly associated with altered gut bacteria. However, whether the microbial dysbiosis that exists in human diabetic patients with or without retinopathy is different remains largely unknown. Here, we collected clinical information and fecal samples from 75 participants, including 25 diabetic patients without retinopathy (DM), 25 diabetic patients with retinopathy (DR), and 25 healthy controls (HC). The gut microbial composition in the three groups was analyzed using 16S ribosomal RNA (rRNA) gene sequencing. Microbial structure and composition differed in the three groups. The α and β diversities in both the DM and DR groups were reduced compared with those in the HC group. Blautia was the most abundant genus, especially in the DM group. In addition, increased levels of Bifidobacterium and Lactobacillus and decreased levels of Escherichia-Shigella, Faecalibacterium, Eubacterium_hallii_group and Clostridium genera were observed in the DM and DR groups compared with the HC group. Furthermore, a biomarker set of 25 bacterial families, which could distinguish patients in the DR group from those in the DM and HC groups was identified, with the area under the curve values ranging from 0.69 to 0.85. Of note, Pasteurellaceae, which was increased in DM and decreased in DR compared with HC, generated a high AUC (0.74) as an individual predictive biomarker. Moreover, 14 family biomarkers were associated with fasting blood glucose levels or diabetes, with most of them being negatively correlated. In summary, our study establishes compositional alterations of gut microbiota in DM and DR, suggesting the potential use of gut microbiota as a non-invasive biomarker for clinical and differential diagnosis, as well as identifying potential therapeutic targets of diabetic retinopathy.

Interpretable Machine Learning Framework Reveals Robust Gut Microbiome Features Associated With Type 2 Diabetes

OBJECTIVE

To identify the core gut microbial features associated with type 2 diabetes risk and potential demographic, adiposity, and dietary factors associated with these features.

RESEARCH DESIGN AND METHODS

We used an interpretable machine learning framework to identify the type 2 diabetes-related gut microbiome features in the cross-sectional analyses of three Chinese cohorts: one discovery cohort (n = 1,832, 270 cases of type 2 diabetes) and two validation cohorts (cohort 1: n = 203, 48 cases; cohort 2: n = 7,009, 608 cases). We constructed a microbiome risk score (MRS) with the identified features. We examined the prospective association of the MRS with glucose increment in 249 participants without type 2 diabetes and assessed the correlation between the MRS and host blood metabolites (n = 1,016). We transferred human fecal samples with different MRS levels to germ-free mice to confirm the MRS-type 2 diabetes relationship. We then examined the prospective association of demographic, adiposity, and dietary factors with the MRS (n = 1,832).

RESULTS

The MRS (including 14 microbial features) consistently associated with type 2 diabetes, with risk ratio for per 1-unit change in MRS 1.28 (95% CI 1.23-1.33), 1.23 (1.13-1.34), and 1.12 (1.06-1.18) across three cohorts. The MRS was positively associated with future glucose increment (P < 0.05) and was correlated with a variety of gut microbiota-derived blood metabolites. Animal study further confirmed the MRS-type 2 diabetes relationship. Body fat distribution was found to be a key factor modulating the gut microbiome-type 2 diabetes relationship.

CONCLUSIONS

Our results reveal a core set of gut microbiome features associated with type 2 diabetes risk and future glucose increment.

Immunomodulation of dendritic cells by Lactobacillus reuteri surface components and metabolites

BACKGROUND

Lactic acid bacteria are commensal members of the gut microbiota and are postulated to promote host health. Secreted factors and cell surface components from Lactobacillus species have been shown to modulate the host immune system. However, the precise role of L. reuteri secreted factors and surface proteins in influencing dendritic cells (DCs) remains uncharacterized.

HYPOTHESIS

We hypothesize that L. reuteri secreted factors will promote DC maturation, skewing cells toward an anti-inflammatory phenotype. In acute colitis, we speculate that L. reuteri promotes IL-10 and dampens pro-inflammatory cytokine production, thereby improving colitis.

METHODS & RESULTS

Mouse bone marrow-derived DCs were differentiated into immature dendritic cells (iDCs) via IL-4 and GM-CSF stimulation. iDCs exposed to L. reuteri secreted factors or UV-irradiated bacteria exhibited greater expression of DC maturation markers CD83 and CD86 by flow cytometry. Additionally, L. reuteri stimulated DCs exhibited phenotypic maturation as denoted by cytokine production, including anti-inflammatory IL-10. Using mouse colonic organoids, we found that the microinjection of L. reuteri secreted metabolites and UV-irradiated bacteria was able to promote IL-10 production by DCs, indicating potential epithelial-immune cross-talk. In a TNBS-model of acute colitis, L. reuteri administration significantly improved histological scoring, colonic cytokine mRNA, serum cytokines, and bolstered IL-10 production.

CONCLUSIONS

Overall these data demonstrate that both L. reuteri secreted factors and its bacterial components are able to promote DC maturation. This work points to the specific role of L. reuteri in modulating intestinal DCs.

NEW & NOTEWORTHY

Lactobacillus reuteri colonizes the mammalian gastrointestinal tract and exerts beneficial effects on host health. However, the mechanisms behind these effects have not been fully explored. In this article, we identified that L. reuteri ATTC PTA 6475 metabolites and surface components promote dendritic cell maturation and IL-10 production. In acute colitis, we also demonstrate that L. reuteri can promote IL-10 and suppress inflammation. These findings may represent a crucial mechanism for maintaining intestinal immune homeostasis.

Oral administration of the probiotic bacterium Lactobacillus acidophilus strain L-55 modulates the immunological parameters of the laying hen inoculated with a Newcastle disease virus-based live attenuated vaccine

Probiotic supplements containing living bacteria have attracted interest as a potential source of health benefits for humans and livestock. The aim of this study was to determine whether administration of Lactobacillus acidophilus strain L-55 (LaL-55) enhances the immune response among chicks exposed to a Newcastle disease virus (NDV)-based live attenuated vaccine. Oral administration of LaL-55 augmented the elevation in the total numbers of leukocytes and lymphocytes following inoculation with the NDV-based live attenuated vaccine. Monocyte counts increased after LaL-55 administration independent of inoculation with the NDV vaccine. Among chicks that were administered LaL-55, there was a dose-dependent increase in the NK cell activity measured by a ⁵¹Cr release assay at 2 weeks after the secondary NDV vaccine inoculation. Two weeks after the secondary inoculation with the NDV vaccine, interferon (IFN)-γ-mRNA expression was significantly elevated in mononuclear splenocytes from chicks that were administered LaL-55. Meanwhile, LaL-55 administration did not change the mRNA levels of IFN-α, IFN-β, and interleukin-1β. These results may suggest that coadministration of LaL-55 with an NDV vaccine augments the immune response against the virus. Therefore, LaL-55 may help protect against viral diseases in poultry.

Oral and nasal probiotic administration for the prevention and alleviation of allergic diseases, asthma and chronic obstructive pulmonary disease

Interaction between a healthy microbiome and the immune system leads to body homeostasis, as dysbiosis in microbiome content and loss of diversity may result in disease development. Due to the ability of probiotics to help and modify microbiome constitution, probiotics are now widely used for the prevention and treatment of different gastrointestinal, inflammatory, and, more recently, respiratory diseases. In this regard, chronic respiratory diseases including chronic obstructive pulmonary disease (COPD), asthma and allergic rhinitis are among the most common and complicated respiratory diseases with no specific treatment until now. Accordingly, many studies have evaluated the therapeutic efficacy of probiotic administration (mostly via the oral route and much lesser nasal route) on chronic respiratory diseases. We tried to summarise and evaluate these studies to give a perspective of probiotic therapy via both the oral and nasal routes for respiratory infections (in general) and chronic respiratory diseases (specifically). We finally concluded that probiotics might be useful for allergic diseases. For asthmatic patients, probiotics can modulate serum cytokines and IgE and decrease eosinophilia, but with no significant reduction in clinical symptoms. For COPD, only limited studies were found with uncertain clinical efficacy. For intranasal administration, although some studies propose more efficiency than the oral route, more clinical evaluations are warranted.

The impact of dietary fiber and probiotics in infectious diseases

Although antibiotics are commonly used to treat infectious diseases, emergence of antibiotic resistant strains highlights the necessity for developing novel alternative approaches. Meanwhile, clinically, antibiotics can destroy the gut microbes balance, which is not conducive to the recovery of infectious disorders. As a result, recent studies have begun to explore potential prevention and treatment methods for infectious diseases, starting with more readily available dietary fiber and probiotics. Moreover, researches have shown the personalized nature of host responses to dietary fiber intervention, with outcomes being dependent on individual pre-treatment gut microbes. In this review, we will focus on the roles of dietary fiber and probiotics on infectious diseases, how probiotics and dietary fiber work on infectious diseases and then explore their mechanisms, so as to guide clinical consideration of new therapies for infectious diseases.

Mannan Enhances IL-12 Production by Increasing Bacterial Uptake and Endosomal Degradation in L. acidophilus and S. aureus Stimulated Dendritic Cells

The mannose receptor (MR) is a C-type lectin involved in endocytosis and with a poorly defined ability to modulate cellular activation. We investigated the effect of mannan treatment prior to stimulation of murine bone marrow-derived dendritic cells with the Gram-positive bacteria Lactobacillus acidophilus NCFM (L. acidophilus) on the induction of Interleukin (IL)-12. Mannan enhanced the IL-12 production induced by L. acidophilus in a dose dependent manner (up to 230% enhancement). Additionally, mannan-enhanced IL-12 induction was also demonstrated with another Gram-positive bacteria, Staphylococcus aureus (S. aureus), while an IL-12 reducing effect was seen on Escherichia coli stimulated cells. Furthermore, the expression of Interferon β (Ifnb) was increased in cells treated with mannan prior to stimulation with L. acidophilus. The addition of mannan but not of bacteria led to endocytosis of MR, while addition of mannan prior to L. acidophilus or S. aureus resulted in increased endocytosis of bacteria, a faster killing of endocytosed bacteria, and increased reactive oxygen species production. Expression of signaling lymphocytic activation molecule (SLAMF)1 shown previously to be involved in the facilitation of endosomal degradation was upregulated by mannan but not by L. acidophilus and S. aureus. The IL-12 enhancement by mannan but not the IL-12 induced by the bacteria was abrogated by addition of inhibitors of clathrin coated pits (chlorpromazine and monodansylcadaverine). Furthermore, the addition of acid sphingomyelinase, a facilitator of ceramide raft formation, prior to addition of L. acidophilus enhanced the IL-12 production and the endocytosis of bacteria. In summary, our results show that mannan increases the IL-12 production induced by some Gram-positive bacteria through MR-endocytosis, which increases bacterial endocytosis and endosomal killing. The differential effect of MR activation on the IL-12 production induced by Gram-positive and Gram-negative bacteria may influence the immune response toward allergens and other glycoproteins.

Oncolytic Bacteria and their potential role in bacterium-mediated tumour therapy: a conceptual analysis

As the human microbiota has been confirmed to be of great significance in maintaining health, the dominant bacteria in them have been applied as probiotics to treat various diseases. After the detection of bacteria in tumours, which had previously been considered a sterile region, these bacteria have been isolated and genetically modified for use in tumour therapy. In this review, we sum up the main types of bacteria used in tumour therapy and reveal the mechanisms of both wild type and engineered bacteria in eliminating tumour cells, providing potential possibilities for newly detected, genetically modified, tumour-associated bacteria in anti-tumour therapy.

Dietary fibers as emerging nutritional factors against diabetes: focus on the involvement of gut microbiota

Diabetes mellitus (DM) increases the risk of cardiovascular diseases and other secondary complications, such as nephropathy, neuropathy, retinopathy, etc. The important risk factors for the pathogenesis of DM are aging, family history, sedentary lifestyle, unhealthy dietary habits, and obesity. Evidence from epidemiological studies also indicates that DM is characterized by specific alterations in the human gut microbiota (GM). GM transplantation in rodents and humans revealed that a specific GM constituent can be the cause and not just the consequence of the DM condition and complications. These findings suggest a potential role of GM in human health, disease prevention, and treatment. Dietary intervention studies using dietary fibers (DFs) suggested that modulation of the GM can suppress the metabolic risk markers in humans. However, a causal role of GM in such studies remains unexplored. Long-term follow-up studies disclosed that the diet rich in insoluble and non-viscous fibers are responsible for DF-mediated antidiabetic activities, while soluble and viscous fibers have little influence on DM despite having a profound impact on glycemia. However, general conclusions cannot be drawn simply based on these findings. Long-term follow-up studies are urgently required in this area to explore the therapeutic potential of different DFs in treating DM and to delineate the exact role of GM involvement. Here we review and discuss the signature of GM during DM, antidiabetic activity of metformin via GM modulation, DFs from different sources and their antidiabetic activity, and the possible role of GM involvement.

Dynamic Development of Fecal Microbiome During the Progression of Diabetes Mellitus in Zucker Diabetic Fatty Rats

Background: Although substantial efforts have been made to link the gut microbiota to type 2 diabetes, dynamic changes in the fecal microbiome under the pathological conditions of diabetes have not been investigated.

Methods: Four male Zucker diabetic fatty (ZDF) rats received Purina 5008 chow [protein = 23.6%, Nitrogen-Free Extract (by difference) = 50.3%, fiber (crude) = 3.3%, ash = 6.1%, fat (ether extract) = 6.7%, and fat (acid hydrolysis) = 8.1%] for 8 weeks. A total of 32 stool samples were collected from weeks 8 to 15 in four rats. To decipher the microbial populations in these samples, we used a 16S rRNA gene sequencing approach.

Results: Microbiome analysis showed that the changes in the fecal microbiome were associated with age and disease progression. In all the stages from 8 to 15 weeks, phyla Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria primarily dominated the fecal microbiome of the rats. Although Lactobacillus and Turicibacter were the predominant genera in 8- to 10-week-old rats, Bifidobacterium, Lactobacillus, Ruminococcus, and Allobaculum were the most abundant genera in 15-week-old rats. Of interest, compared to the earlier weeks, relatively greater diversity (at the genus level) was observed at 10 weeks of age. Although the microbiome of 12-week-old rats had the highest diversity, the diversity in 13–15-week-old rats was reduced. Spearman’s correlation analysis showed that F/B was negatively correlated with age. Random blood glucose was negatively correlated with Lactobacillus and Turicibacter but positively correlated with Ruminococcus and Allobaculum and Simpson’s diversity index.

Conclusion: We demonstrated the time-dependent alterations of the abundance and diversity of the fecal microbiome during the progression of diabetes in ZDF rats. At the genus level, dynamic changes were observed. We believe that this work will enhance our understanding of fecal microbiome development in ZDF rats and help to further analyze the role of the microbiome in metabolic diseases. Furthermore, our work may also provide an effective strategy for the clinical treatment of diabetes through microbial intervention.

Vaginal Lactobacilli Induce Differentiation of Monocytic Precursors Toward Langerhans-like Cells: in Vitro Evidence

Lactobacilli have immunomodulatory mechanisms that affect the host cell immune system, leading to inhibition of HIV-1 transmission. Thus, lactobacilli as mucosal delivery vehicles for developing HIV-1 vaccines have attracted interest in recent years. Herein, we investigated the immunomodulatory effects of six strains of Lactobacillus naturally isolated from vaginal samples, including Lactobacillus crispatus (L. crispatus), L. fermentum, L. jensenii, L. gasseri, L. delbrueckii and L. johnsonii, on differentiation of monocytic precursors. L. crispatus, L. fermentum and L. delbrueckii could drive human monocytic cell line THP-1 cells to differentiate into dendritic-like cells according to the morphology. Moreover, L. crispatus increased costimulatory molecules including CD40, CD80 and CD86, and Langerhans cell specific C-type lectin receptors CD207, while L. fermentum decreased these molecules in THP-1 cells. Furthermore, L. crispatus promoted the differentiation of THP-1 cells with specific markers, phagocytic features, cytokine production ability and reduced the expression of receptors for HIV-1 entry of Langerhans cells. However, in the presence of L. fermentum, THP-1 cells did not show the above alterations. Moreover, similar effects of L. crispatus and L. fermentum were observed in CD14⁺ monocytes. These data suggested that L. crispatus facilitates the differentiation of monocytic precursors toward Langerhans-like cells in vitro. We further identified the cell wall components of Lactobacillus and found that peptidoglycans (PGNs), rather than bacteriocins, S-layer protein and lipoteichoic acid, were key contributors to the induction of CD207 expression. However, PGNs originating from Bacillus subtilis, E. coli JM109 and E. coli DH5α did not elevate CD207 expression, indicating that only PGN derived from Lactobacillus could enhance CD207 expression. Finally, the recognized receptors of L. crispatus (such as TLR2 and TLR6) and the upstream transcription factors (PU.1, TAL1, TIF1γ, and POLR2A) of CD207 were examined, and the expression of these molecules was enhanced in THP-1 cells following L. crispatus treatment. Thus, this study offers powerful evidence that vaginal lactobacilli modulate monocytic precursor differentiation into Langerhans-like cells probably via activating the TLR2/6-TFs-CD207 axis. These data provide clues for further investigation of the original occurrence, development and differentiation of Langerhans cells from monocytes.

Immunological Tolerance and Function: Associations Between Intestinal Bacteria, Probiotics, Prebiotics, and Phages

Post-birth there is a bacterial assault on all mucosal surfaces. The intestinal microbiome is an important participant in health and disease. The pattern of composition and concentration of the intestinal microbiome varies greatly. Therefore, achieving immunological tolerance in the first 3-4 years of life is critical for maintaining health throughout a lifetime. Probiotic bacteria are organisms that afford beneficial health effects to the host and in certain instances may protect against the development of disease. The potential benefits of modifying the composition of the intestinal microbial cohort for therapeutic benefit is evident in the use in high risks groups such as premature infants, children receiving antibiotics, rotavirus infections in non-vaccinated children and traveler's diarrhea in adults. Probiotics and prebiotics are postulated to have immunomodulating capabilities by influencing the intestinal microbial cohort and dampening the activity of pathobiont intestinal microbes, such as Klebsiella pneumonia and Clostridia perfringens. Lactobacilli and Bifidobacteria are examples of probiotics found in the large intestine and so far, the benefits afforded to probiotics have varied in efficacy. Most likely the efficacy of probiotic bacteria has a multifactorial dependency, namely on a number of factors that include agents used, the dose, the pattern of dosing, and the characteristics of the host and the underlying luminal microbial environment and the activity of bacteriophages. Bacteriophages, are small viruses that infect and lyse intestinal bacteria. As such it can be posited that these viruses display an effective local protective control mechanism for the intestinal barrier against commensal pathobionts that indirectly may assist the host in controlling bacterial concentrations in the gut. A co-operative activity may be envisaged between the intestinal epithelia, mucosal immunity and the activity of bacteriophages to eliminate pathobiots, highlighting the potential role of bacteriophages in assisting with maintaining intestinal homeostasis. Hence bacteriophage local control of inflammation and immune responses may be an additional immunological defense mechanism that exploits bacteriophage-mucin glycoprotein interactions that controls bacterial diversity and abundance in the mucin layers of the gut. Moreover, and importantly the efficacy of probiotics may be dependent on the symbiotic incorporation of prebiotics, and the abundance and diversity of the intestinal microbiome encountered. The virome may be an important factor that determines the efficacy of some probiotic formulations.

Bifidobacterium animalis ssp. lactis Bb12 induces IL-10 through cell membrane-associated components via TLR2 in swine

AIM

To investigate the role of Toll-like receptor 2 (TLR2) in interleukin-10 (IL-10) production induced by Bifidobacterium animalis ssp. lactis Bb12 (Bb12) in swine immune cells.

METHODS AND RESULTS

Blood-monocytes and cells from mesenteric lymph nodes were obtained from pigs and cultured with live Bb12 for 4 and 12 h. Transcript levels of IL-10 and TLR2 were analysed. Furthermore, TLR2 was blocked to determine its participation in IL-10 production. TLR2 blockade was achieved with neutralizing antibodies, followed by stimulation with Bb12. Bifidobacteria induced IL-10 production in both swine monocytes and mesenteric cells. Monocytes with TLR2 blockade had a decrease in IL-10 transcripts, while mesenteric cells did not. Bacterial cell wall components were responsible for Bb12-induced IL-10 production since no IL-10 was detected in the culture supernatant.

CONCLUSIONS

We demonstrated that IL-10 production is largely mediated through the recognition of Bb12 structures by TLR2, as bacterial metabolites in the culture supernatant failed to induce IL-10 expression.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study provides evidence for the potential use of Bb12 in the swine industry; these bacteria can also be used as additional method to treat intestinal inflammation and enhance intestinal health in pigs.

Synbiotic Effects of the Dietary Fiber Long-Chain Inulin and Probiotic Lactobacillus acidophilus W37 Can be Caused by Direct, Synergistic Stimulation of Immune Toll-Like Receptors and Dendritic Cells

SCOPE

Synbiotic effects of dietary fibers and lactobacilli are usually explained by synergistic modulation of gut microbiota. New insight, however, has demonstrated that both dietary fibers and lactobacilli can directly stimulate immune cells and benefit consumer immunity. Here, the synergistic effects of immune active long-chain inulin (lcITF) and Lactobacillus acidophilus W37 (LaW37) on dendritic cells (DCs) are investigated.

METHODS AND RESULTS

Effects of lcITF and LaW37 alone or combined were studied on Toll-like receptor (TLRs) signaling and cytokine secretion by DCs in the presence and absence of media of intestinal epithelial cell (IEC) exposed to the ingredients. Also, the effects of DC responses against Salmonella Typhimurium (STM) were investigated. Synergistic effects were observed on TLR2 and 3. Synergistic effects were not always pro-inflammatory. LaW37 was strongly pro-inflammatory, while cytokine responses were regulatory when combined with lcITF. Exposure of DCs to IECs medium changed the DCs' response, which revealed synergistic enhancing effects of lcITF/LaW37 on production of IL-6 and IL-8. DCs' response in the presence of STM and LaW37 were so strong that lcITF had no additional effect.

CONCLUSION

It is demonstrated that synbiotic effects of dietary fibers and bacteria are not limited to the effects on gut microbiota but can also occur by synergistically directly stimulating IECs and/or immune cells.

A Polysaccharide Isolated from Dictyophora indusiata Promotes Recovery from Antibiotic-Driven Intestinal Dysbiosis and Improves Gut Epithelial Barrier Function in a Mouse Model

Despite the tremendous biological activity of polysaccharides from the mushroom Dictyophora indusiata, its role in the restoration of gut microbiota has not yet been explored. The present study aimed to investigate whether D. indusiata polysaccharide (DIP) could modulate the recovery of gut microbiota composition and intestinal barrier function after broad-spectrum antibiotic-driven dysbiosis. Alteration and restoration in the microbial communities were elucidated by the Illumina MiSeq platform. Colon histology, expression of tight-junction associated proteins, and serum/tissue endotoxin and cytokine levels were evaluated. Two-week daily oral administration of clindamycin and metronidazole resulted in reduced bacterial diversity and richness, and perturbed the microbial flora at various taxonomic levels (altered Firmicutes/Bacteroidetes ratio and increased relative abundance of harmful flora (Proteobacteria, Enterococcus, and Bacteroides)), whereas DIP administration reversed the dysbiosis and increased beneficial flora, including Lactobacillaceae (lactic acid-producing bacteria), and Ruminococaceae (butyrate-producing bacteria). In addition, it resulted in the reduction of endotoxemia (through lipopolysaccharides (LPSs)) and pro-inflammatory cytokine (tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β)) levels, with the increased expression of tight-junction associated proteins (claudin-1, occludin, and zonula occludens-1). These findings not only suggested a comprehensive understanding of the protective effects of a DIP in the restoration of gut microbiota but also highlighted its role in the enhancement of gut barrier integrity, reduction of inflammation and lowering of endotoxin levels in mice.

Comparison of the common bacteria in human and mouse tumours using high-throughput sequencing

Evidence has indicated that gut bacteria may serve an important role in cancer development and therapy, while little work has been done to explore the microbial diversity inside tumours. In the present study, high‑throughput sequencing was first used to identify and compare the microbial diversity in human and mouse tumours. Principal component analysis (PCA) and β-diversity indicated a low microbial similarity among mouse artificial tumours (M.AT group), mouse spontaneous tumours (M.T group) and human tumours (H.T group), and Serratia (35.85 vs. 32.64 vs. 73.32%), Pseudomonas (24.10 vs. 16.62 vs. 1.72%) and Ochrobactrum (6.28 vs. 11.08 vs. 11.90%) were identified as dominant bacteria at the genus level. In addition, Venn results indicated 103 common operational taxonomic units (OTUs) in the M.AT, M.T and H.T groups, and only 2 and 1 OTUs belonged to Lactobacillus and Escherichia, respectively, while no OTUs belonging to Salmonella, Bifidobacteria or Clostridium were identified. In the present study, the common bacteria between human and mouse tumours were identified, which may serve as potential strains for bacteriotherapy of cancers.

Deciphering bacterial community changes in zucker diabetic fatty rats based on 16S rRNA gene sequences analysis

The aim of the present pilot study was deciphering bacterial community changes in Zucker diabetic fatty rats (ZDF rats), a model of type 2 diabetes. Recent studies unmasked that the status of gastrointestinal tract microbiota has a marked impact on nutrition-related syndromes such as obesity and type-2 diabetes (T2D). In this study, samples taken from the gastrointestinal tracts (GI tracts) of ZDF and their lean littermates (ZL rats) were subjected to 16S rRNA gene sequence-based analysis to examine the characteristic bacterial communities, including those located in the stomach, duodenum, jejunum, ileum, cecum and feces. Results revealed that the Firmicutes/Bacteroidetes ratio was increased and greater numbers of Lactobacillus were detected along GI tracts in ZDF rats compared to ZL rats. In conclusion, this work is the first study to systematically characterize bacterial communities along ZDF rat GI tract and provides substantial evidence supporting a prospective strategy to alter the GI microbial communities improving obesity and T2D.

Immunogenicity in chickens with orally administered recombinant chicken-borne Lactobacillus saerimneri expressing FimA and OmpC antigen of O78 avian pathogenic Escherichia coli

PURPOSE

Avian colibacillosis is responsible for economic losses to poultry producers worldwide. To combat this, we aimed to develop an effective oral vaccine for chicken against O78 avian pathogenic Escherichia coli (APEC) infection through a Lactobacillus delivery system.

METHODOLOGY

Eight Lactobacillus strains isolated from the intestines of broiler chickens were evaluated based on their in vitro adherence ability to assess their potential as a delivery vector. Fimbrial subunit A (FimA) and outer-membrane protein C (OmpC) of APEC with and without fusion to dendritic cell-targeting peptide (DCpep) and microfold cell-targeting peptide (Co1) were displayed on the surface of Lactobacillus saerimneri M-11 and yielded vaccine groups (pPG-ompC-fimA/M-11 and pPG-ompC-fimA-Co1-DCpep/M-11, respectively). The colonization of the recombinant strains in vivo was assessed and the immunogenicity and protective efficacy of orally administered recombinant strains in chickens were evaluated.

RESULTS

The colonization of the recombinant strains in vivo revealed no significant differences between the recombinant and wild-type strains. Chickens orally administered with vaccine groups showed significantly higher levels of OmpC/FimA-specific IgG in serum and mucosal IgA in cecum lavage, nasal lavage and stool compared to the pPG/M-11 group. After challenge with APEC CVCC1553, better protective efficacy was observed in chickens orally immunized with pPG-ompC-fimA/M-11 and pPG-ompC-fimA-Co1-DCpep/M-11, but no significant differences were observed between the two groups.

CONCLUSIONS

Recombinant chicken-borne L. saerimneri M-11 showed good immunogenicity in chickens, suggesting that it may be a promising vaccine candidate against APEC infections. However, the activity of mammalian DCpep and Co1 was not significant in chickens.

Fecal Microbiota Transplantation, Commensal Escherichia coli and Lactobacillus johnsonii Strains Differentially Restore Intestinal and Systemic Adaptive Immune Cell Populations Following Broad-spectrum Antibiotic Treatment

The essential role of the intestinal microbiota in the well-functioning of host immunity necessitates the investigation of species-specific impacts on this interplay. Aim of this study was to examine the ability of defined Gram-positive and Gram-negative intestinal commensal bacterial species, namely Escherichia coli and Lactobacillus johnsonii, respectively, to restore immune functions in mice that were immunosuppressed by antibiotics-induced microbiota depletion. Conventional mice were subjected to broad-spectrum antibiotic treatment for 8 weeks and perorally reassociated with E. coli, L. johnsonii or with a complex murine microbiota by fecal microbiota transplantation (FMT). Analyses at days (d) 7 and 28 revealed that immune cell populations in the small and large intestines, mesenteric lymph nodes and spleens of mice were decreased after antibiotic treatment but were completely or at least partially restored upon FMT or by recolonization with the respective bacterial species. Remarkably, L. johnsonii recolonization resulted in the highest CD4+ and CD8+ cell numbers in the small intestine and spleen, whereas neither of the commensal species could stably restore those cell populations in the colon until d28. Meanwhile less efficient than FMT, both species increased the frequencies of regulatory T cells and activated dendritic cells and completely restored intestinal memory/effector T cell populations at d28. Furthermore, recolonization with either single species maintained pro- and anti-inflammatory immune functions in parallel. However, FMT could most effectively recover the decreased frequencies of cytokine producing CD4+ lymphocytes in mucosal and systemic compartments. E. coli recolonization increased the production of cytokines such as TNF, IFN-γ, IL-17, and IL-22, particularly in the small intestine. Conversely, only L. johnsonii recolonization maintained colonic IL-10 production. In summary, FMT appears to be most efficient in the restoration of antibiotics-induced collateral damages to the immune system. However, defined intestinal commensals such as E. coli and L. johnsonii have the potential to restore individual functions of intestinal and systemic immunity. In conclusion, our data provide novel insights into the distinct role of individual commensal bacteria in maintaining immune functions during/following dysbiosis induced by antibiotic therapy thereby shaping host immunity and might thus open novel therapeutical avenues in conditions of perturbed microbiota composition.

Polysaccharides from Chrysanthemum morifolium Ramat ameliorate colitis rats by modulating the intestinal microbiota community

The gut microflora dysbiosis has been closely related with the inflammatory bowel disease (IBD). In this study, the effect of polysaccharides from Chrysanthemum morifolium Ramat on the gut microbiota was evaluated by ulcerative colitis (UC) rat model. Physiological and pathological analyses suggested that Chrysanthemum polysaccharides possessed notably protective effects on UC in vivo. Based on the Illumina MiSeq platform, 16S rRNA sequencing of the rat colonic contents indicated that the intestinal flora structure remarkably changed in the model rats and the tendency was alleviated to a certain degree by treatment with different dosages of Chrysanthemum polysaccharides. In normal groups, there were more Firmicutes than Bacteroidetes, but this change lost at the pathological state. Following Chrysanthemum polysaccharides, rising Firmicutes/Bacteroidetes ratio was validated. Besides the microbial diversity and the community richness of the UC rats were improved by Chrysanthemum polysaccharides, the composition of intestinal microflora in the model group were also restored after oral administration of Chrysanthemum polysaccharides. The abundance of opportunistic pathogens was decreased (Escherichia, Enterococcus and Prevotella), while the levels of protective bacteria such as Butyricicoccus and Clostridium (butyrate-producing bacteria), Lactobacillus and Bifidobacterium (probiotics), Lachnospiraceae and Rikenellaceae elevated in various degrees. Correlation analysis between intestinal flora and biochemical factors suggested that the relative abundance of protective bacteria was positively correlated with the levels of anti-inflammatory cytokines such as IL-4, IL-10 and IL-11, while aggressive bacteria were positively correlated with proinflammatory cytokine such as IL-23、IL-6、 IF-17、TNF-α、IL-1β and IFN-γ. The above results showed that the intestinal flora were closely related to the secretion and expression of cytokines in the body, and they interacted with each other to regulate immune function. Thus, Chrysanthemum polysaccharides could ameliorate ulcerative colitis by fostering beneficial intestinal flora growth, modulating the balance of intestinal microecology and restoring the immune system.

Gleaning Insights from Fecal Microbiota Transplantation and Probiotic Studies for the Rational Design of Combination Microbial Therapies

Beneficial microorganisms hold promise for the treatment of numerous gastrointestinal diseases. The transfer of whole microbiota via fecal transplantation has already been shown to ameliorate the severity of diseases such as Clostridium difficile infection, inflammatory bowel disease, and others. However, the exact mechanisms of fecal microbiota transplant efficacy and the particular strains conferring this benefit are still unclear. Rationally designed combinations of microbial preparations may enable more efficient and effective treatment approaches tailored to particular diseases. Here we use an infectious disease, C. difficile infection, and an inflammatory disorder, the inflammatory bowel disease ulcerative colitis, as examples to facilitate the discussion of how microbial therapy might be rationally designed for specific gastrointestinal diseases. Fecal microbiota transplantation has already shown some efficacy in the treatment of both these disorders; detailed comparisons of studies evaluating commensal and probiotic organisms in the context of these disparate gastrointestinal diseases may shed light on potential protective mechanisms and elucidate how future microbial therapies can be tailored to particular diseases.

In situ delivery and production system of trastuzumab scFv with Bifidobacterium

A monoclonal antibody targeting human epidermal growth factor receptor-2 (HER2), trastuzumab has become a standard treatment for HER2-positive breast cancer. Recent advancements in antibody engineering have enabled the efficient generation of the trastuzumab single-chain variable fragment (scFv). In this study, we genetically engineered Bifidobacterium, a bacterial strain shown to accumulate safely and selectively in hypoxic tumor sites by intravenous (iv) injection, to express and secrete the trastuzumab scFv. The recombinant scFv bound to cell surface HER2 and inhibited in vitro growth of HER2-positive human cancer cells. Moreover, iv-injected recombinant bacteria specifically localized and secreted trastuzumab scFv in xenografted human HER2-positive tumors and consequently inhibited tumor growth. The development and results of this novel in situ delivery and production system for trastuzumab scFv with Bifidobacterium represents a promising avenue for future application in cancer treatment.

The regulation of immune cells by Lactobacilli: a potential therapeutic target for anti-atherosclerosis therapy

Atherosclerosis is an inflammatory disease regulated by several immune cells including lymphocytes, macrophages and dendritic cells. Gut probiotic bacteria like Lactobacilli have been shown immunomodificatory effects in the progression of atherogenesis. Some Lactobacillus stains can upregulate the activity of regulatory T-lymphocytes, suppress T-lymphocyte helper (Th) cells Th1, Th17, alter the Th1/Th2 ratio, influence the subsets ratio of M1/M2 macrophages, inhibit foam cell formation by suppressing macrophage phagocytosis of oxidized low-density lipoprotein, block the activation of the immune system with dendritic cells, which are expected to suppress the atherosclerosis-related inflammation. However, various strains can have various effects on inflammation. Some other Lactobacillus strains were found have potential pro-atherogenic effect through promote Th1 cell activity, increase pro-inflammatory cytokines levels as well as decrease anti-inflammatory cytokines levels. Thus, identifying the appropriate strains is essential to the therapeutic potential of Lactobacilli as an anti-atherosclerotic therapy.

Unraveling the Differences between Gram-Positive and Gram-Negative Probiotics in Modulating Protective Immunity to Enteric Infections

The role of intestinal microbiota and probiotics in prevention and treatment of infectious diseases, including diarrheal diseases in children and animal models, is increasingly recognized. Intestinal commensals play a major role in development of the immune system in neonates and in shaping host immune responses to pathogens. Lactobacilli spp. and Escherichia coli Nissle 1917 are two probiotics that are commonly used in children to treat various medical conditions including human rotavirus diarrhea and inflammatory bowel disease. Although the health benefits of probiotics have been confirmed, the specific effects of these established Gram-positive (G+) and Gram-negative (G−) probiotics in modulating immunity against pathogens and disease are largely undefined. In this review, we discuss the differences between G+ and G− probiotics/commensals in modulating the dynamics of selected infectious diseases and host immunity. These probiotics modulate the pathogenesis of infectious diseases and protective immunity against pathogens in a species- and strain-specific manner. Collectively, it appears that the selected G− probiotic is more effective than the various tested G+ probiotics in enhancing protective immunity against rotavirus in the gnotobiotic piglet model.

Searching for the Perfect Homeostasis: Five Strains of Bifidobacterium longum From Centenarians Have a Similar Behavior in the Production of Cytokines

GOALS

To investigate the modulation of human cytokines by Bifidobacterium longum strains isolated from Centenarians. In particular, we measured the production of interleukin (IL)-12p70, interferon-γ, IL-17A, and IL-4 from human peripheral blood mononuclear cells after stimulation with live bacteria.

BACKGROUND

Probiotics may inhibit pathogens and modulate the immune system, bringing a beneficial effect on human health. Among the probiotic strains, bifidobacteria play a key role in the maturation of the host's immune system. At present, only a few comparative data are available on the effects of bifidobacteria associations on cytokine production.

STUDY

Peripheral blood mononuclear cells were isolated, cultured, and stimulated (ratio 1:1) with B. longum DLBL07, B. longum DLBL08, B. longum DLBL09, B. longum DLBL10, or B. longum DLBL11, either alone or in association. Cytokine production was determined by an enzyme-linked immunosorbent assay.

RESULTS

Both the B. longum DLBL mixture and the individual B. longum DLBL strains induced similar levels of IL-4, interferon-γ, and IL-17A. Under all conditions tested, no IL-12p70 release was detected.

CONCLUSIONS

The fact that B. longum strains were obtained from Centenarians suggests a perfect homeostasis between this specific species and the host. Moreover all the B. longum strains from Centenarians used in our study share some biological similarities.

Lactobacillus delbrueckii subsp lactis CIDCA 133 modulates response of human epithelial and dendritic cells infected with Bacillus cereus

It is known that probiotic microorganisms are able to modulate pathogen virulence. This ability is strain dependent and involves multiple interactions between microorganisms and relevant host's cell populations. In the present work we focus on the effect of a potentially probiotic lactobacillus strain (Lactobacillus delbrueckii subsp. lactis CIDCA 133) in an in vitro model of Bacillus cereus infection. Our results showed that infection of intestinal epithelial HT-29 cells by B. cereus induces nuclear factor kappa B (NF-κB) pathway. Noteworthy, the presence of strain L. delbrueckii subsp.lactis CIDCA 133 increases stimulation. However, B. cereus-induced interleukin (IL)-8 production by epithelial cells is partially abrogated by L. delbrueckii subsp. lactis CIDCA 133. These findings suggest that signalling pathways other than that of NF-κB are involved. In a co-culture system (HT-29 and monocyte-derived dendritic cells), B. cereus was able to translocate from the epithelial (upper) to the dendritic cell compartment (lower). This translocation was partially abrogated by the presence of lactobacilli in the upper compartment. In addition, infection of epithelial cells in the co-culture model, led to an increase in the expression of CD86 by dendritic cells. This effect could not be modified in the presence of lactobacilli. Interestingly, infection of enterocytes with B. cereus triggers production of proinflammatory cytokines by dendritic cells (IL-8, IL-6 and tumour necrosis factor alpha (TNF-α)). The production of TNF-α (a protective cytokine in B. cereus infections) by dendritic cells was increased in the presence of lactobacilli. The present work demonstrates for the first time the effect of L. delbrueckii subsp. lactis CIDCA 133, a potentially probiotic strain, in an in vitro model of B. cereus infection. The presence of the probiotic strain modulates cell response both in infected epithelial and dendritic cells thus suggesting a possible beneficial effect of selected lactobacilli strains on the course of B. cereus infection.

Lactobacillus crispatus strain SJ-3C-US induces human dendritic cells (DCs) maturation and confers an anti-inflammatory phenotype to DCs

Lactobacillus crispatus is one of the most predominant species in the healthy vagina microbiota. Nevertheless, the interactions between this commensal bacterium and the immune system are largely unknown. Given the importance of the dendritic cells (DCs) in the regulation of the immunity, this study was performed to elucidate the influence of vaginal isolated L. crispatus SJ-3C-US from healthy Iranian women on DCs, either directly by exposure of DCs to ultraviolet-inactivated (UVI) and heat-killed (HK) L. crispatus SJ-3C-US or indirectly to its cell-free supernatant (CFS), and the outcomes of immune response. In this work we showed that L. crispatus SJ-3C-US induced strong dose-dependent activation of dendritic cells and production of high levels of IL-10, whereas IL-12p70 production was induced at low level in an inverse dose-dependent manner. This stimulation skewed T cells polarization toward CD4(+) CD25(+) FOXP3(+) Treg cells and production of IL-10 in a dose-dependent manner in mixed leukocyte reaction (MLR) test. The mode of bacterial inactivation did not affect the DCs activation pattern, upon encounter with L. crispatus SJ-3C-US. Moreover, while DCs stimulated with CFS showed moderate phenotypic maturation and IL-10 production, it failed to skew T cells polarization toward CD4(+) CD25(+) FOXP3(+) regulatory T cells (Treg) and production of IL-10. This study showed that L. crispatus SJ-3C-US confers an anti-inflammatory phenotype to DCs through up-regulation of anti-inflammatory/regulatory IL-10 cytokine production and induction of CD4(+) CD25(+) FOXP3(+) T cells at optimal dosage. Our findings suggest that L. crispatus SJ-3C-US could be a potent candidate as protective probiotic against human immune-mediated pathologies, such as chronic inflammation, vaginitis or pelvic inflammatory disease (PID).

Health effects of probiotics on the skin

Skin is the largest organ of the body and is constantly exposed to physical, chemical, bacterial, and fungal challenges. It is well known that probiotics are helpful for specific disorders and different clinical studies have indicated that probiotics have special effects in cutaneous apparatus directly or indirectly that can be considerable from versatile aspects. Probiotic bacteriotherapy can have great potential in preventing and treating the skin diseases including eczema, atopic dermatitis, acne, and allergic inflammation or in skin hypersensitivity, UV-induced skin damage, wound protection, and as a cosmetic product. The current paper comprehensively reviews the different health effects of probiotics on the skin.

Metagenomic insights into tetracycline effects on microbial community and antibiotic resistance of mouse gut

Antibiotics have been widely used for disease prevention and treatment of the human and animals, and for growth promotion in animal husbandry. Antibiotics can disturb the intestinal microbial community, which play a fundamental role in animals' health. Misuse or overuse of antibiotics can result in increase and spread of microbial antibiotic resistance, threatening human health and ecological safety. In this study, we used Illumina Hiseq sequencing, (1)H nuclear magnetic resonance spectroscopy and metagenomics approaches to investigate intestinal microbial community shift and antibiotic resistance alteration of the mice drinking the water containing tetracycline hydrochloride (TET). Two-week TET administration caused reduction of gut microbial diversity (from 194 to 89 genera), increase in Firmicutes abundance (from 24.9 to 39.8%) and decrease in Bacteroidetes abundance (from 69.8 to 51.2%). Metagenomic analysis showed that TET treatment affected the intestinal microbial functions of carbohydrate, ribosomal, cell wall/membrane/envelope and signal transduction, which is evidenced by the alteration in the metabolites of mouse serum. Meanwhile, in the mouse intestinal microbiota, TET treatment enhanced the abundance of antibiotic resistance genes (ARGs) (from 307.3 to 1492.7 ppm), plasmids (from 425.4 to 3235.1 ppm) and integrons (from 0.8 to 179.6 ppm) in mouse gut. Our results indicated that TET administration can disturb gut microbial community and physiological metabolism of mice, and increase the opportunity of ARGs and mobile genetic elements entering into the environment with feces discharge.

Divergent signaling pathways regulate IL-12 production induced by different species of Lactobacilli in human dendritic cells

Recent studies have indicated that different strains of Lactobacilli differ in their ability to regulate IL-12 production by dendritic cells (DCs), as some strains are stronger inducer of IL-12 while other are not and can even inhibit IL-12 production stimulated by IL-12-inducer Lactobacilli. In this report we demonstrate that Lactobacillus reuteri 5289, as previously described for other strains of L. reuteri, can inhibit DC production of IL-12 induced by Lactobacilllus acidophilus NCFM. Remarkably, L. reuteri 5289 was able to inhibit IL-12 production induced not only by Lactobacilli, as so far reported, but also by bacteria of different genera, including pathogens. We investigated in human DCs the signal transduction pathways involved in the inhibition of IL-12 production induced by L. reuteri 5289, showing that this potential anti-inflammatory activity, which is also accompanied by an elevated IL-10 production, is associated to a prolonged phosphorilation of ERK1/2 MAP kinase pathway. Improved understanding of the immune regulatory mechanisms exerted by Lactobacilli is crucial for a more precise employment of these commensal bacteria as probiotics in human immune-mediated pathologies, such as allergies or inflammatory bowel diseases.

Differential effects of lactobacilli on activation and maturation of mouse dendritic cells

Lactic acid bacteria (LAB) are of interest because of their potential to modulate immune responses. The effects of LAB range from regulation to stimulation of the immune system. A series of studies were performed in vitro to study the effects of six lactic acid bacteria (LAB), Lactobacillus helveticus LH-2, Lactobacillus acidophilus La-5, La-115, La-116 and La-14, and Lactobacillus salivarius, on maturation and activation of mouse dendritic cells. Production of tumour necrosis factor (TNF)-?, interleukin (IL)-6 and IL-10 by dendritic cells (DCs) was determined after treating cells with live LAB. The expression of DC maturation markers, CD80 and CD40, was also measured using flow cytometry after stimulation with LAB. In addition, the expression of Toll-like receptors (TLRs) 2, 4 and 9 by DCs stimulated with LAB was measured. Our results revealed that LAB act differentially on pro-inflammatory and anti-inflammatory cytokine production and induction of co-stimulatory molecules by DCs. Specifically, L. salivarius was found to be the most effective LAB to induce pro-inflammatory cytokine production and expression of co-stimulatory molecules. Moreover, La-14, La-116 and La-5 induced moderate maturation and activation of DCs. On the other hand, LH-2 and La-115 were the least effective lactobacilli to induce DC responses. The present study also revealed that L. salivarius was able to induce the expression of TLR2, 4 and 9 by DCs. In conclusion, various strains and species of LAB can differentially regulate DC activation and maturation, providing further evidence that these bacteria may have the ability to influence and steer immune responses in vivo.

Adjuvant effects of L. acidophilus LW1 on immune responses to the foot-and-mouth disease virus DNA vaccine in mice

The adjuvant effects of Lactobacillus acidophilus on DNA vaccination are not fully understood. It has been hypothesized that swine-derived Lactobacillus acidophilus SW1 (LASW1) could function as an immune adjuvant to enhance antigen-specific immune responses after foot-and-mouth disease (FMD) DNA vaccination in mice. To evaluate the effect of oral LASW1 on the immune response to a DNA vaccine (pRC/CMV-vp1) harboring FMD VP1 gene, anti-FMDV antibody and its isotypes, T-cell proliferation, and cytokine detection were investigated. The results showed that LASW1 was able to enhance FMDV-specific antibody levels and FMDV-neutralizing antibodies. After a booster vaccine, the anti-FMDV antibody titers and FMDV-neutralizing antibodies levels induced by pRC/CMV-vp1 were higher in mice treated with LSAW1 than in the group immunized with pRC/CMV-vp1 alone (the control). Using T-cell proliferation, the stimulation index of the LASW1 group was significantly higher in response to ConA and 146S antigen (P<0.05) than in the control group. Importantly, higher concentrations of IFN-γ and IFN-γ-producing cells were also observed in splenocytes isolated from the experimental LASW1 mice, indicating that INF-γ secretion is important to the immune response to LASW1. The results indicate that LASW1 is a promising immune adjuvant in DNA vaccination against FMD when administrated orally.

Lactobacillus acidophilus L-92 Cells Activate Expression of Immunomodulatory Genes in THP-1 Cells

To understand the immunomodulatory effects of Lactobacillus acidophilus L-92 cells suggested from our previous study of in vivo anti-allergy and anti-virus effects, host immune responses in macrophage-like THP-1 cells after 4 h (the early phase) and 24 h (the late phase) of cocultivation with L-92 cells were investigated by transcriptome analysis. In the early phase of L-92 treatment, various transcription regulator genes, such as, NFkB1, NFkB2, JUN, HIVEP2 and RELB, and genes encoding chemokines and cytokines, such as CCL4, CXCL11, CCL3 and TNF, were upregulated. Two transmembrane receptor genes, TLR7 and ICAM1, were also upregulated in the early phase of treatment. In contrast, many transmembrane receptor genes, such as IL7R, CD80, CRLF2, CD86, CD5, HLA-DQA1, IL2RA, IL15RA and CSF2RA, and some cytokine genes, including IL6, IL23A and CCL22, were significantly upregulated in the late phase after L-92 exposure. Some genes encoding cytokines, such as IL1A, IL1B and IL8, and the enzyme IDO1 were upregulated at both the early and the late phases of treatment. These results suggest that probiotic L-92 might promote Th1 and regulatory T-cell responses by activation of the MAPK signaling pathway, followed by the NOD-like receptor signaling pathway in THP-1 cells.