Effect of supplementation with Lactobacillus rhamnosus GG powder on intestinal and liver damage in broiler chickens challenged by lipopolysaccharide

This study explores the effect of dietary along with Lactobacillus rhamnosus GG (LGG) powder on intestinal and liver damage in broiler chickens challenged by lipopolysaccharide (LPS). A total of 100 healthy 1-day-old Ross 308 broiler chickens were selected and randomly divided into two treatments: the control group and the LGG treatment group. There were five replicates for each group, with 10 chickens per replicate. The chickens in the control group were fed a basal diet, while LGG treatment was supplemented with 1,000 mg/kg LGG along with the basal diet. The experiment lasted 29 days, and the trial included two phases. During the first 27 days, the animals were weighed on the 14th and 27th days to calculate growth performance. Then, on day 29, 2 animals from each replicate were intraperitoneally injected with 1 mg/kg BW LPS, and another 2 animals were treated with an equal volume of saline. The chickens were slaughtered 3 h later for sampling and further analysis. (1) LGG addition to the diet did not affect growth performance, including average daily gain (ADG), average daily feed intake (ADFI), and feed-to-weight ratio (F/G) of broiler chickens; (2) LPS stimulation decreased villus height (VH), and caused oxidative stress and increased the amount of diamine oxidase (DAO) in plasma, and the relative expression of intestinal inflammation genes (interleukin-8 [IL-8], interleukin 1β [IL-1β], inducible nitric oxide synthase [iNOS], and tumor necrosis factor-α [TNF-α]) and the relative expression of liver injury genes (b-cell lymphoma 2 [BCL2], heat shock protein70 [HSP70], and matrix metallopeptidase 13 [MMP13]). (3) Supplementation of LGG increased VH and the relative expression of intestinal barrier genes (mucins 2 [Mucin2] and occludin [Occludin]) and decreased the amount of DAO in plasma and the relative expression of intestinal inflammatory factors (IL-8, iNOS, and IL-1β). LGG supplementation also increased the expression of liver injury-related genes (MMP13 and MMP9). In conclusion, LGG enhanced intestinal barrier function, improved intestinal morphology, and alleviated the intestines' inflammatory response in LPS-stimulated broiler chicken, and it has a slightly protective effect on liver damage.

Lactobacillus rhamnosus inhibits osteoclast differentiation by suppressing the TLR2/NF-κB pathway

OBJECTIVE

This study aimed to investigate the role of ultrasonicated Lactobacillus rhamnosus extract in osteoclast differentiation and its underlying mechanism, providing new strategies for the treatment of periodontitis.

MATERIALS AND METHODS

Osteoclasts were induced using macrophage colony-stimulating factor and receptor activator for nuclear factor-κB ligand. Lactobacillus rhamnosus extracts were obtained via ultrasonic crushing and ultracentrifugation. The effects of the LGG extract on osteoclast differentiation were evaluated, and the related signaling pathways were examined using western blotting. A mouse periodontitis model was established, and Lactobacillus rhamnosus extract was injected into the gingival sulcus to evaluate the inhibitory effect of Lactobacillus rhamnosus extract on alveolar bone resorption.

RESULTS

At 50 μg/mL, Lactobacillus rhamnosus extract inhibited osteoclast differentiation with no effect on apoptosis and proliferation. This phenomenon was achieved by deactivating the NF-κB/c-Fos/NFATc1 signaling pathway through toll-like receptor 2. The in vivo results showed that the local injection of Lactobacillus rhamnosus extract suppressed osteoclast differentiation and alveolar bone resorption.

CONCLUSION

The ultrasonicated extract of Lactobacillus rhamnosus inhibited osteoclast differentiation by suppressing the activation of the NF-κB/c-Fos/NFATc1 pathway. Furthermore, it inhibited the destruction of the alveolar bone, providing a new strategy for the use of probiotics in the treatment of periodontitis.

Recent advances in understanding of multifaceted changes in the vaginal microenvironment: implications in vaginal health and therapeutics

The vagina endures multifaceted changes from neonatal to menopausal phases due to hormonal flux, metabolite deposition, and microbial colonization. These features have important implications in women's health. Several pre-factors show dynamic characteristics according to the phases that shift the vaginal microbiota from anaerobes to aerobes which is a hallmark of healthy vaginal environment. These factors include oestrogen levels, glycogen deposition, and vaginal microstructure. In the adult phase, Lactobacillus is highly dominant and regulates pH, adherence, aggregation, immune modulation, synthesis of bacteriocins, and biosurfactants (BSs) which are antagonistic to pathogens. Maternal factors are protective by favouring the colonization of lactobacilli in the vagina in the neonatal phase, which diminishes with age. The dominance of lactobacilli and dysbiosis in the adult phase depends on intrinsic and extrinsic factors in women, which vary between ethnicities. Recent developments in probiotics used against vaginal microbiome dysbiosis have shown great promise in restoring the normal microbiota including preventing the loss of beneficial bacteria. However, further in-depth studies are warranted to ensure long-term protection by probiotics. This review highlights various aspects of the vaginal microenvironment in different phases of growth and diverse ethnicities. Furthermore, it discusses future trends for formulating more effective population-specific probiotics and implications of paraprobiotics and postbiotics as effective therapeutics.

Lactobacillus rhamnosus GG Attenuates Lipopolysaccharide-Induced Inflammation and Barrier Dysfunction by Regulating MAPK/NF-κB Signaling and Modulating Metabolome in the Piglet Intestine

BACKGROUND

Probiotic Lactobacillius rhamnosus GG (LGG) shows beneficial immunomodulation on cultured cell lines in vitro and in mouse models.

OBJECTIVE

The aim was to investigate the effects of LGG on intestinal injury and the underlying mechanisms by elucidating inflammatory signaling pathways and metabolomic response to LPS stimulation in the piglet intestine.

METHODS

Piglets (Duroc × Landrace × Large White, including males and female; 8.6 ± 1.1 kg) aged 28 d were assigned to 3 groups (n = 6/group): oral inoculation with PBS for 2 wk before intraperitoneal injection of physiological saline [control (CON)] or LPS (25 μg/kg body weight; LPS) or oral inoculation with LGG for 2 wk before intraperitoneal injection of LPS (LGG+LPS). Piglets were killed 4 h after LPS injection. Systemic inflammation, intestinal integrity, inflammation signals, and metabolomic characteristics in the intestine were determined.

RESULTS

Compared with CON, LPS stimulation significantly decreased ileal zonula occludens 1 (ZO-1; 44%), claudin-3 (44%), and occludin (41%) expression; increased serum diamineoxidase (73%), D-xylose (19%), TNF-α (43%), and IL-6 (55%) concentrations; induced p38 mitogen-activated protein kinase (p38 MAPK; 85%), extracellular signal-regulated kinase (ERK; 96%), and NF-κB p65 phosphorylation (37%) (P < 0.05). Compared with LPS stimulation alone, LGG pretreatment significantly enhanced the intestinal barrier by upregulating expressions of tight junction proteins (ZO-1, 73%; claudin-3, 55%; occludin, 67%), thereby decreasing serum diamineoxidase (26%) and D-xylose (28%) concentrations, and also reduced serum TNF-α expression (16%) and ileal p38 MAPK (79%), ERK (43%) and NF-κB p65 (37%) phosphorylation levels (P < 0.05). Metabolomic analysis showed clear separation between each group. The concentrations of caprylic acid [fold-change (FC) = 2.39], 1-mono-olein (FC = 2.68), erythritol (FC = 4.62), and ethanolamine (FC = 4.47) significantly increased in the intestine of LGG + LPS piglets compared with the LPS group (P < 0.05).

CONCLUSIONS

These data suggest that LGG alleviates gut inflammation, improves intestinal barrier function, and modulates the metabolite profile of piglets challenged with LPS. This trial was registered at the Zhejiang University (http://www.lac.zju.edu.cn) as ZJU20170529.

Lactobacillus rhamnosus GG components, SLP, gDNA and CpG, exert protective effects on mouse macrophages upon lipopolysaccharide challenge

The aim of this study was to determine whether Lactobacillus rhamnosus GG (LGG) components (surface layer protein, SLP; genomic DNA, gDNA; unmethylated cytosine-phosphate-guanine-containing oligodeoxynucleotide, CpG-ODN), alone or in combination, could affect immunomodulation, and evaluate the signalling mechanism in mouse macrophage RAW264.7 cells challenged with lipopolysaccharide (LPS). LGG components were used to treat cells before LPS stimulation. Cytokine and Toll-like receptor (TLR) expression were assessed using real-time quantitative PCR (RT-qPCR). Mitogen-activated protein kinase (MAPK), extracellular regulated protein kinase (ERK) and nuclear factor-kappa B (NF-κB) signalling pathways were evaluated using immunoblots and immunofluorescence. SLP or SLP + gDNA pre-treatment significantly reduced the LPS-induced mRNA expression of tumour necrosis factor alpha (TNF-α). Pre-treatment with LGG single components (SLP, gDNA or CpG) or their combinations (SLP + gDNA or SLP + CpG) significantly decreased the LPS-induced interleukin-6 (IL-6) mRNA level (P < 0·05). Pre-treatment with SLP or gDNA, alone or in combination, significantly suppressed LPS-induced TLR2 and TLR4 mRNA levels (P < 0·05). SLP pre-treatment also significantly decreased the LPS-induced expression of TLR9 (P < 0·05). Pre-treatment with LGG single components or combinations significantly suppressed the LPS-induced phosphorylation levels of ERK (P > 0·05). In conclusion, pre-incubation with LGG components, singly or in combination, generally inhibited the activation of TLR, MAPK and NF-κB signalling pathways in LPS-stimulated cells, leading to attenuated inflammatory cytokine TNF-α and IL-6 production. These results indicate that nonviable probiotic LGG components exert an anti-inflammation effect on epithelial cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus rhamnosus GG (LGG) is widely used as probiotics. However, its main components are not well known for affecting immunomodulation. This study investigated the effects of pre-treatments with different components such as surface layer protein, genomic DNA and unmethylated cytosine-phosphate-guanine-containing oligodeoxynucleotides, alone or in combination on immunomodulation, and evaluated the signalling mechanism in mouse macrophage RAW264.7 cells challenged with lipopolysaccharide. Pre-incubation with components alone or in combination generally inhibited the activation of Toll-like receptor, mitogen-activated protein kinases, extracellular regulated protein kinases and nuclear factor-kappa B signalling pathways in lipopolysaccharide-stimulated cells, which generally leads to attenuated inflammatory cytokine interleukin-6 and tumour necrosis factor alpha production. These results indicate that nonviable probiotic LGG components exert an anti-inflammation effect on epithelial cells.

Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus

This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM), moisture content, Fourier Transform Infrared Spectrometry (FTIR), thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g) was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.

Flow cytometry as an auxiliary tool for the selection of probiotic bacteria

Selection of appropriate bacterial strains is crucial for development of new probiotic preparations. The fundamental prerequisite for potential efficacy of a probiotic preparation for oral application is the selection of appropriate bacterial strains with good gastrointestinal colonisation abilities, antimicrobial activity, and tolerance of conditions in the gastrointestinal tract, resistance to different antimicrobial agents, survival during processing and storage. The strain should be genetically stable, it should have good growth properties, to maintain its high viability at processing and when in storage. Mostly, the properties of promising strains are tested in the first phase in vitro, and only the best ones undergo subsequent in vivo testing. in vitro tests are often performed by classical microbiological cultivation methods which are material and time consuming, and they are not able to distinguish between ‘viable but nonculturable’ and dead bacteria. Flow cytometry is usually used for counting, phenotyping or functional characterisation of immune cells. Nowadays, flow cytometry is increasingly used in microbiology for counting bacteria, determining their viability and metabolic activity, detecting specific strains or testing their adherence abilities. The utilisation of flow cytometry in combination with an appropriate fluorescent labelling represents an effective and rapid method for the selection of probiotic bacteria.

Spatial Localization and Binding of the Probiotic Lactobacillus farciminis to the Rat Intestinal Mucosa: Influence of Chronic Stress

The present study aimed at detecting the exogenously applied probiotic Lactobacillus farciminis in rats, after exposure to IBS-like chronic stress, based on 4-day Water Avoidance Stress (WAS). The presence of L. farciminis in both ileal and colonic mucosal tissues was demonstrated by FISH and qPCR, with ileum as the preferential niche, as for the SFB population. A different spatial distribution of the probiotic was observed: in the ileum, bacteria were organized in micro-colonies more or less close to the epithelium whereas, in the colon, they were mainly visualized far away from the epithelium. When rats were submitted to WAS, the L. farciminis population substantially decreased in both intestinal regions, due to a stress-induced increase in colonic motility and defecation, rather than a modification of bacterial binding to the intestinal mucin Muc2.

An L-Fucose Operon in the Probiotic Lactobacillus rhamnosus GG Is Involved in Adaptation to Gastrointestinal Conditions

L-Fucose is a sugar present in human secretions as part of human milk oligosaccharides, mucins, and other glycoconjugates in the intestinal epithelium. The genome of the probiotic Lactobacillus rhamnosus GG (LGG) carries a gene cluster encoding a putative L-fucose permease (fucP), L-fucose catabolic pathway (fucI, fucK, fucU, and fucA), and a transcriptional regulator (fucR). The metabolism of L-fucose in LGG results in 1,2-propanediol production, and their fucI and fucP mutants displayed a severe and mild growth defect on L-fucose, respectively. Transcriptional analysis revealed that the fuc genes are induced by L-fucose and subject to a strong carbon catabolite repression effect. This induction was triggered by FucR, which acted as a transcriptional activator necessary for growth on L-fucose. LGG utilized fucosyl-α1,3-N-acetylglucosamine and contrarily to other lactobacilli, the presence of fuc genes allowed this strain to use the L-fucose moiety. In fucI and fucR mutants, but not in fucP mutant, L-fucose was not metabolized and it was excreted to the medium during growth on fucosyl-α1,3-N-acetylglucosamine. The fuc genes were induced by this fucosyl-disaccharide in the wild type and the fucP mutant but not in a fucI mutant, showing that FucP does not participate in the regulation of fuc genes and that L-fucose metabolism is needed for FucR activation. The l-fucose operon characterized here constitutes a new example of the many factors found in LGG that allow this strain to adapt to the gastrointestinal conditions.

Adhesion properties of Lactobacillus rhamnosus mucus-binding factor to mucin and extracellular matrix proteins

We previously described potential probiotic Lactobacillus rhamnosus strains, isolated from fermented mare milk produced in Sumbawa Island, Indonesia, which showed high adhesion to porcine colonic mucin (PCM) and extracellular matrix (ECM) proteins. Recently, mucus-binding factor (MBF) was found in the GG strain of L. rhamnosus as a mucin-binding protein. In this study, we assessed the ability of recombinant MBF protein from the FSMM22 strain, one of the isolates of L. rhamnosus from fermented Sumbawa mare milk, to adhere to PCM and ECM proteins by overlay dot blot and Biacore assays. MBF bound to PCM, laminin, collagen IV, and fibronectin with submicromolar dissociation constants. Adhesion of the FSMM22 mbf mutant strain to PCM and ECM proteins was significantly less than that of the wild-type strain. Collectively, these results suggested that MBF contribute to L. rhamnosus host colonization via mucin and ECM protein binding.

Inhibitory effect of Lactobacillus salivarius on Streptococcus mutans biofilm formation

Dental caries arises from an imbalance of metabolic activities in dental biofilms developed primarily by Streptococcus mutans. This study was conducted to isolate potential oral probiotics with antagonistic activities against S. mutans biofilm formation from Lactobacillus salivarius, frequently found in human saliva. We analysed 64 L. salivarius strains and found that two, K35 and K43, significantly inhibited S. mutans biofilm formation with inhibitory activities more pronounced than those of Lactobacillus rhamnosus GG (LGG), a prototypical probiotic that shows anti-caries activity. Scanning electron microscopy showed that co-culture of S. mutans with K35 or K43 resulted in significantly reduced amounts of attached bacteria and network-like structures, typically comprising exopolysaccharides. Spot assay for S. mutans indicated that K35 and K43 strains possessed a stronger bactericidal activity against S. mutans than LGG. Moreover, quantitative real-time polymerase chain reaction showed that the expression of genes encoding glucosyltransferases, gtfB, gtfC, and gtfD was reduced when S. mutans were co-cultured with K35 or K43. However, LGG activated the expression of gtfB and gtfC, but did not influence the expression of gtfD in the co-culture. A transwell-based biofilm assay indicated that these lactobacilli inhibited S. mutans biofilm formation in a contact-independent manner. In conclusion, we identified two L. salivarius strains with inhibitory activities on the growth and expression of S. mutans virulence genes to reduce its biofilm formation. This is not a general characteristic of the species, so presents a potential strategy for in vivo alteration of plaque biofilm and caries.

Comparative genomic and functional analysis of 100 Lactobacillus rhamnosus strains and their comparison with strain GG

Lactobacillus rhamnosus is a lactic acid bacterium that is found in a large variety of ecological habitats, including artisanal and industrial dairy products, the oral cavity, intestinal tract or vagina. To gain insights into the genetic complexity and ecological versatility of the species L. rhamnosus, we examined the genomes and phenotypes of 100 L. rhamnosus strains isolated from diverse sources. The genomes of 100 L. rhamnosus strains were mapped onto the L. rhamnosus GG reference genome. These strains were phenotypically characterized for a wide range of metabolic, antagonistic, signalling and functional properties. Phylogenomic analysis showed multiple groupings of the species that could partly be associated with their ecological niches. We identified 17 highly variable regions that encode functions related to lifestyle, i.e. carbohydrate transport and metabolism, production of mucus-binding pili, bile salt resistance, prophages and CRISPR adaptive immunity. Integration of the phenotypic and genomic data revealed that some L. rhamnosus strains possibly resided in multiple niches, illustrating the dynamics of bacterial habitats. The present study showed two distinctive geno-phenotypes in the L. rhamnosus species. The geno-phenotype A suggests an adaptation to stable nutrient-rich niches, i.e. milk-derivative products, reflected by the alteration or loss of biological functions associated with antimicrobial activity spectrum, stress resistance, adaptability and fitness to a distinctive range of habitats. In contrast, the geno-phenotype B displays adequate traits to a variable environment, such as the intestinal tract, in terms of nutrient resources, bacterial population density and host effects.

Some bacterial species are specialists and adapted to a single niche, while others are generalists and able to grow in various environmental conditions. Lactobacillus rhamnosus is a generalist and its members can often be found in different human cavities but also in various artisanal and industrial dairy products. To gain insights into the genetic complexity and ecological versatility of this species, we collected 100 L. rhamnosus strains from different niches. Genomic and functional analysis of these revealed a dichotomy within the species that reflected its adaptation to particular niches. The variable regions identified in the L. rhamnosus genome encode lifestyle traits that allowed us to demonstrate that some L. rhamnosus isolates possibly resided in multiple habitats. Our work brings valuable data on the ecological dynamics and adaptability of the species and provides a basis for a model explaining the ecology of L. rhamnosus in an anthropocentric perspective. Finally, we observed that a set of pheno-genomic markers, i.e. CRISPR oligotyping or carbohydrate metabolism, would be sufficient and among the best ways to differentiate the L. rhamnosus strains, providing a general approach to select the highest diversity in these and other bacterial species.

Adhesion and nanomechanics of pili from the probiotic Lactobacillus rhamnosus GG

Knowledge of the mechanisms by which bacterial pili adhere to host cells and withstand external forces is critical to our understanding of their functional roles and offers exciting avenues in biomedicine for controlling the adhesion of bacterial pathogens and probiotics. While much progress has been made in the nanoscale characterization of pili from Gram-negative bacteria, the adhesive and mechanical properties of Gram-positive bacterial pili remain largely unknown. Here, we use single-molecule atomic force microscopy to unravel the binding mechanism of pili from the probiotic Gram-positive bacterium Lactobacillus rhamnosus GG (LGG). First, we show that SpaC, the key adhesion protein of the LGG pilus, is a multifunctional adhesin with broad specificity. SpaC forms homophilic trans-interactions engaged in bacterial aggregation and specifically binds mucin and collagen, two major extracellular components of host epithelial layers. Homophilic and heterophilic interactions display similar binding strengths and dissociation rates. Next, pulling experiments on living bacteria demonstrate that LGG pili exhibit two unique mechanical responses, that is, zipper-like adhesion involving multiple SpaC molecules distributed along the pilus length and nanospring properties enabling pili to resist high force. These mechanical properties may represent a generic mechanism among Gram-positive bacterial pili for strengthening adhesion and withstanding shear stresses in the natural environment. The single-molecule experiments presented here may help us to design molecules capable of promoting or inhibiting bacterial-host interactions.

Behavior of lactobacilli isolated from fermented slurry (ben-saalga) in gnotobiotic rats

Most bacterial strains, which have been studied so far for their probiotic functions, are extensively used by manufacturers in developed countries. In our work, we sought to study a mix (called BSL) comprising three strains belonging to Lactobacillus fermentum, L. paraplantarum and L. salivarius, that were isolated from a traditional African pearl millet based fermented slurry. Our objective was to study this BSL cocktail in gnotobiotic rats, to evaluate their survival and their behavior in the digestive tract conditions. After a single oral inoculation of germfree rats with BSL, the species established stably in the digestive tract with the following hierarchy of abundance: L. salivarius> L. plantarum> L. fermentum. BSL cocktail was metabolically active since it produced 50 mM lactate and it expressed genes involved in binding mechanism in the caecum. Furthermore, the global morphology of the colon epithelium was not disturbed by the BSL cocktail. BSL cocktail did not modify mucus content and host mucus-related genes (MUC1, MUC2, MUC3 or resistin-like molecule β). The cocktail of lactobacilli enhanced the proliferating cell nuclear antigen (PCNA) at a level comparable to what was observed in conventional rats. PCNA was involved in proliferation and DNA repair, but the presence of the cocktail did not provoke proliferative events (with Ki67 as indicator), so we suppose BSL may help gut preservation. This work is the first step towards the selection of strains that are derived from traditional fermented food to formulate new probiotic mixture.

A, Call J, Luchansky J, Phillips J, Liu LS, Yam K. Protection of probiotic bacteria in a synbiotic matrix following aerobic storage at 4 °C

The survival of single strains of Bifidobacterium breve, Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus reuteri was investigated in synbiotics that included 10 mg/ml of fructo-oligosaccharides, inulin and pectic-oligosaccharides in an alginate matrix under refrigerated (4 °C) aerobic storage conditions. When the matrices were cross-linked with calcium (45 mM), 102-103 cfu/ml of L. acidophilus and L. reuteri, and 0-103 cfu/ml of B. breve and B. longum survived refrigerated aerobic storage for 28 days. Following refrigerated storage, acetic (3-9 mM), butyric (0-2 mM), propionic (5-16 mM) and lactic acids (1-48 mM) were produced during the growth of probiotics in BHI broth at 37 °C, suggesting their metabolic activity after storage was stressed. When calcium cross-linking was not used in synbiotics, the matrix remained more gel-like after inoculation when compared to the calcium cross-linked matrix. At least 107 cfu/ml of probiotic bacteria survived after 21 days of storage within these gel-like alginate matrices. Significantly higher levels of B. breve, L. acidophilus and L. reuteri were obtained from the synbiotic matrices supplemented with fructo-oligosaccharides, inulin and pectic-oligosaccharides compared to alginate alone. B. longum survival was the same (~7 logs) in all gel-like synbiotic matrices. These results show that synbiotics protected probiotic bacteria and extended their shelf-life under refrigerated aerobic conditions. Synbiotics represent a viable delivery vehicle for health-promoting bacteria.