Regulation of toll-like receptors-mediated inflammation by immunobiotics in bovine intestinal epitheliocytes: role of signaling pathways and negative regulators

Bacteroides thetaiotaomicron and its inactivated bacteria ameliorate colitis by inhibiting macrophage activation

BACKGROUND

Studies have demonstrated that Bacteroides thetaiotaomicron (BT) has protective effect against colon inflammation in murine models. Macrophages play an important role in gut immunity. However, the specific mechanisms of BT on macrophage are still unelucidated. Thus, our study investigates the anti-inflammatory effect of BT and its heat-treated inactivated bacteria on experimental colitis and macrophages.

METHODS

A dextran sulfate sodium (DSS)-induced acute colitis model with male C57BL/6 mice, BT (ATCC29148) strain, THP1 cell lines were used in this study. Live and heat-treated inactivated BT (IBT) solution (1 × 10^9cfu/ml) were intragastrically gavaged daily for 14 days. Colonic inflammation was determined by the disease activity index (DAI) score, colon length, histological score, and inflammatory factors. THP1 cells were induced towards M1, then treated with different concentrations of inactivated BT solution and p38 inhibitor. Western blotting, immunohistochemistry, immunofluorescence and qRT-PCR were performed to assess the levels of inflammatory cytokines and molecules of MAPK pathway including IL-6, TNF-α, IL-1β, IL-22, p38 and phosphor-p38 expressions. Moreover, 16S rRNA sequencing of colitis murine fecal samples was applied to investigate the influence of supplementation of BT to the gut microbiota homeostasis.

RESULTS

Both live and heat-treated inactivated BT decreased the DAI and histological scores as well as levels of inflammatory factors, particularly IL-6 while increasing IL-22 of DSS-induced colitis murine models. The cell experiments showed that inactivated BT downregulates IL-6 expression in THP1 via inhibiting p38 phosphorylation and affecting M1 polarization. Moreover, the 16S rRNA sequencing results showed that BT and IBT gavage could increase beta-diversity of gut flora in DSS-induced colitis mice. Furthermore, the significance test for differences between the groups showed that BT could increase Faecalebaculum, Lactobacillus and Bacteroides, while decreasing Akkermansia.

CONCLUSION

In summary, our findings imply that BT and its heat-treated inactivated bacteria exert a protective effect by suppressing macrophage-induced IL-6 through the inhibition of p38 MAPK pathway and ameliorating intestinal gut dysbiosis in experimental colitis.

Lacticaseibacillus rhamnosus HN001 alters the microbiota composition in the cecum but not the feces in a piglet model

The probiotic Lacticaseibacillus rhamnosus strain HN001 has been shown to have several beneficial health effects for both pediatric and maternal groups, including reduced risk of eczema in infants and gestational diabetes and postnatal depression in mothers. While L. rhamnosus HN001 appears to modify immune and gut barrier biomarkers, its mode of action remains to be fully elucidated. To gain insights into the role of HN001 on the infant microbiome, the impacts of L. rhamnosus HN001 supplementation was studied in 10-day old male piglets that were fed either infant formula, or infant formula with L. rhamnosus HN001 at a low (1.3 × 10⁵ CFU/ml) or high dose (7.9 × 10⁶ CFU/ml) daily for 24 days. The cecal and fecal microbial communities were assessed by shotgun metagenome sequencing and host gene expression in the cecum and colon tissue was assessed by RNA-seq. Piglet fecal samples showed only modest differences between controls and those receiving dietary L. rhamnosus HN001. However, striking differences between the three groups were observed for cecal samples. While total lactobacilli were significantly increased only in the high dose L. rhamnosus HN001 group, both high and low dose groups showed an up to twofold reduction across the Firmicutes phylum and up to fourfold increase in Prevotella compared to controls. Methanobrevibacter was also decreased in HN001 fed piglets. Microbial genes involved in carbohydrate and vitamin metabolism were among those that differed in relative abundance between those with and without L. rhamnosus HN001. Changes in the cecal microbiome were accompanied by increased expression of tight junction pathway genes and decreased autophagy pathway genes in the cecal tissue of piglets fed the higher dose of L. rhamnosus HN001. Our findings showed supplementation with L. rhamnosus HN001 caused substantial changes in the cecal microbiome with likely consequences for key microbial metabolic pathways. Host gene expression changes in the cecum support previous research showing L. rhamnosus HN001 beneficially impacts intestinal barrier function. We show that fecal samples may not adequately reflect microbiome composition higher in the gastrointestinal tract, with the implication that effects of probiotic consumption may be missed by examining only the fecal microbiome.

Biological roles of toll-like receptors and gut microbiota in colorectal cancer

Colorectal cancer (CRC) is one of the most considerably common malignancies of the alimentary system, with high mortality and incidence rates.  The present study suggested that the occurrence of CRC is closely related to bacteria, as the large intestine is a gathering place for human micro-organisms. However, the nosogenesis of bacteria leading to tumorigenesis is still obscure. Recently, many studies have reported that toll-like receptors and their related molecular pathways are involved in the process of gut micro-organisms generating CRC. Gut micro-organisms can promote or inhibit the development of CRC via binding to special toll-like receptors. In this paper, the authors review the relationship among toll-like receptors, gut micro-organisms and CRC in order to provide a reference for future tumor immunotherapy and targeted therapy.

Sodium butyrate administration modulates the ruminal villus height, inflammation-related gene expression, and plasma hormones concentration in dry cows fed a high-fiber diet

The objectives of this study were to evaluate the effects of sodium butyrate on the ruminal villus morphology, mRNA expression associated with nutrient metabolism and inflammation in the ruminal epithelium, and plasma concentrations of metabolites and hormones in non-lactating cows fed a high-fiber diet. Four Holstein cows with a rumen cannula were assigned to two treatments in a crossover design. The treatments were ruminal administration of sodium butyrate premix or control premix before feeding to cows fed the same total mixed ration mainly composed of glass silage once a day. Sodium butyrate was provided at a butyrate dose of 0.04% per kg body weight. The control premix was made by replacing sodium-butyrate with wheat bran. The plasma β-hydroxybutyrate concentration increased 3 to 6 h after the butyrate premix administration but returned to a concentration similar to that of the control before feeding. After continuous administration, increases in the ruminal villus height and plasma concentration of glucagon-like peptide-2, and lower gene expression of TNF-α, IL-1β, and TLR-2 in the rumen epithelium were observed in cows supplied with the butyrate premix. These results showed that sodium butyrate affects rumen epithelial morphology and plasma concentrations of hormones even under a low fermentable diet.

The effect of sodium butyrate supplementation on ruminal and fecal pH and serum lipopolysaccharide-binding protein after ruminal acidosis challenge in nonlactating cows

The objective of this study was to evaluate effects of sodium-butyrate supplementation on gastrointestinal function and the inflammatory response to ruminal acidosis (RA) challenge in cows. Four nonlactating cows with a rumen cannula were assigned to two treatments in a crossover design. Treatments were ruminal administration of sodium-butyrate (BUT) or control (CON). Sodium-butyrate was provided as Gustor BP70 and administered at a butyrate dose of 0.04% per kg body weight. The CON premix was made by replacing sodium-butyrate with wheat bran. Experimental periods were 28 days long with 21-day washout period separating the treatments. On Day 25 of each period, corn starch was ruminally administered at 0.7% per kg body weight as RA challenge. After RA challenge, ruminal pH was lower, and endotoxin concentration was higher for cows provided with BUT than those with CON, but the increase in fecal starch and the decrease in fecal pH were attenuated by BUT. The effect of butyrate supplementation on serum lipopolysaccharide-binding protein after RA challenge was not found. From these findings, butyrate supplementation mitigated rectal acidosis by reducing the flux of fermentable carbohydrate into the large intestine. An anti-inflammatory effect of butyrate was not observed, possibly due to lower pH and higher endotoxin concentration in the rumen.

Bovine Immunology: Implications for Dairy Cattle

The growing world population (7.8 billion) exerts an increased pressure on the cattle industry amongst others. Intensification and expansion of milk and beef production inevitably leads to increased risk of infectious disease spread and exacerbation. This indicates that improved understanding of cattle immune function is needed to provide optimal tools to combat the existing and future pathogens and improve food security. While dairy and beef cattle production is easily the world's most important agricultural industry, there are few current comprehensive reviews of bovine immunobiology. High-yielding dairy cattle and their calves are more vulnerable to various diseases leading to shorter life expectancy and reduced environmental fitness. In this manuscript, we seek to fill this paucity of knowledge and provide an up-to-date overview of immune function in cattle emphasizing the unresolved challenges and most urgent needs in rearing dairy calves. We will also discuss how the combination of available preventative and treatment strategies and herd management practices can maintain optimal health in dairy cows during the transition (periparturient) period and in neonatal calves.

Association between Toll-like receptor gene polymorphisms and risk of Helicobacter pylori infection: A protocol for systematic review and meta-analysis

BACKGROUND

There were many case-control studies performed the association between TLRs gene polymorphisms and the correlation of Helicobactor pylori infection, these results were inconformity. Therefore, a comprehensive meta-analysis was performed to evaluate the TLRs gene polymorphism and susceptibility to H. pylori infection.

METHODS

Eligible studies were searched from PubMed, EMBASE, Web of science, Cochrane library, CNKI, CBM, Wan Fang Database and VIP Database, all the databases were searched from inception to December 2020. OR with the corresponding 95% CI were presented as associations between certain TLR gene polymorphism and the risk of H. pylori infection, all the included data will be analyzed with the software of Review Manager 5.2 and STATA 14.2.

RESULTS

This study will provide a high-quality evidence to find the TLR gene polymorphisms with H. pylori infection susceptibility.

CONCLUSION

This study will explore which TLR genotype increase the risk of H. pylori infection.

Combined use of lactic-acid-producing bacteria as probiotics and rotavirus vaccine candidates expressing virus-specific proteins

Due to the lower efficacy of currently approved live attenuated rotavirus (RV) vaccines in developing countries, a new approach to the development of safe mucosally administered live bacterial vectors is being considered, using probiotic bacteria as an efficient delivery platform for heterologous RV antigens. Lactic acid bacteria (LAB), which are considered food-grade bacteria and normal microbiota, have been utilized throughout history as probiotics and developed since the 1990s as a delivery system for recombinant heterologous proteins. Over the last decade, LAB have frequently been used as a platform for the delivery of various RV antigens to the mucosa. Given the appropriate safety profile for neonates and providing the benefits of probiotics, recombinant LAB-based vaccines could potentially address the need for a subunit RV vaccine. The present review focuses mainly on different recombinant LAB vaccine constructs for RV and their potential as an alternative recombinant vaccine against RV disease.

Effects of butyrate supplementation on blood glucagon-like peptide-2 concentration and gastrointestinal functions of lactating dairy cows fed diets differing in starch content

The objective of this study was to evaluate effects of butyrate supplementation on plasma concentration of glucagon-like peptide-2 (GLP-2), apparent total-tract digestibility, and responses to a grain challenge of lactating dairy cows fed diets differing in starch content. Eight Holstein cows averaging 58.6 ± 9.96 d in milk (4 primiparous cows fitted with rumen cannula and 4 multiparous intact cows) were blocked by parity and assigned to one of two 4 × 4 Latin squares balanced for carryover effects with a 2 × 2 factorial arrangement of treatments. Treatments were dietary starch content [20.6 vs. 27.5%, respectively, for low starch (LS) and high starch (HS)] and butyrate supplementation (butyrate vs. control) with 21-d periods. Butyrate was provided as Gustor BP70 WS (Norel, S.A., Madrid, Spain), containing 70% sodium butyrate and 30% fatty acid mixture, at 2% of dietary dry matter (providing butyrate at 1.1% of dietary dry matter), and control premix contained 70% wheat bran and 30% fatty acid mixture. Feeds, orts, and fecal samples were collected from d 17 to 19 to determine apparent total-tract nutrient digestibility. Blood and rumen fluid samples were collected on d 19. The baseline of dry matter intake (DMI) was determined as average DMI from d 17 to 19 for each cow, and cows were feed-restricted at 60% of the baseline DMI on d 20, and a grain challenge was conducted by providing steam-flaked corn grain at 0.6% of body weight, on an as-fed basis, in addition to each treatment diet on d 21, and blood and ruminal fluid samples were collected. The interaction of dietary starch content by butyrate supplementation was significant for plasma GLP-2 concentration, being greater for cows fed butyrate with the HS diet than those fed the other 3 diets. Cows fed butyrate increased n-butyrate concentration in the ruminal fluid and tended to increase dry matter and organic matter digestibility compared with the control. During the grain challenge, rumen endotoxin concentration increased over time and was higher for cows fed the HS diets compared with those fed LS diets. However, response variables related to inflammation were not affected by the grain challenge. However, serum haptoglobin, lipopolysaccharide-binding protein, and serum amyloid-A concentrations were greater for cows fed butyrate with the LS diet, but not for those fed the HS diet. These results indicate that butyrate supplementation may increase plasma GLP-2 concentration for cows fed HS diets, and total-tract digestibility regardless of dietary starch content. However, butyrate supplementation did not mitigate inflammation in this study.

The Control of Intestinal Inflammation: A Major Objective in the Research of Probiotic Strains as Alternatives to Antibiotic Growth Promoters in Poultry

The reduction of antimicrobial resistance is a major challenge for the scientific community. In a few decades, infections by resistant bacteria are forecasted to be the main cause of death in the world. The withdrawal of antibiotics as growth promoters and their preventive use in animal production is essential to avoid these resistances, but this may impair productivity and health due to the increase in gut inflammation. This reduction in productivity aggravates the problem of increasing meat demand in developing countries and limits the availability of raw materials. Probiotics are promising products to address this challenge due to their beneficial effects on microbiota composition, mucosal barrier integrity, and immune system to control inflammation. Although many modes of action have been demonstrated, the scientific community is not able to describe the specific effects that a probiotic should induce on the host to maximize both productivity and animal health. First, it may be necessary to define what are the innate immune pathways acting in the gut that optimize productivity and health and to then investigate which probiotic strain is able to induce the specific effect needed. This review describes several gaps in the knowledge of host-microbiota-pathogen interaction and the related mechanisms involved in the inflammatory response not demonstrated yet in poultry.

Heat-Killed Bifidobacterium breve B-3 Enhances Muscle Functions: Possible Involvement of Increases in Muscle Mass and Mitochondrial Biogenesis

A previous clinical study on pre-obesity subjects revealed that Bifidobacteriumbreve B-3 shows anti-obesity effects and possibly increases muscle mass. Here, we investigated the effects of B-3 on muscle function, such as muscle strength and metabolism, and some signaling pathways in skeletal muscle. Male rodents were orally administered live B-3 (B-3L) or heat-killed B-3 (B-3HK) for 4 weeks. We found that administration of B-3 to rats tended to increase muscle mass and affect muscle metabolism, with stronger effects in the B-3HK group than in the B-3L group. B-3HK significantly increased muscle mass and activated Akt in the rat soleus. With regard to muscle metabolism, B-3HK significantly increased phosphorylated AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and cytochrome c oxidase (CCO) gene expression in the rat soleus, suggesting an effect on the AMPK-PGC1α-mitochondrial biogenesis pathway. Furthermore, B-3HK promoted oxidative muscle fiber composition in the gastrocnemius. We also observed a significantly higher level of murine grip strength in the B-3HK group than in the control group. These findings suggest the potential of heat-killed B-3 in promoting muscle hypertrophy and modifying metabolic functions, possibly through the Akt and AMPK pathways, respectively.

TLR4 increases the stemness and is highly expressed in relapsed human hepatocellular carcinoma

Toll‐like receptor 4 (TLR4) plays an essential role in cancer progress. Here, we find that the expression of TLR4 in relapsed human hepatocellular carcinoma (HCC) clinical samples is higher than that in the non‐relapsed ones, which leads us to explore the role of TLR4 in cancer stemness. We reported that TLR4‐AKT signaling pathway was activated by lipopolysaccharides (LPS) in HCC cell lines to enhance the cancer stemness capacity, which was reflected by the increased percentage of CD133⁺CD49f⁺ population and side population, enhanced sphere formation, and the upregulation of stemness marker gene‐SOX2. Downregulation of SOX2 attenuated the enhanced HCC stemness induced by LPS, indicating SOX2 as a downstream mediator of LPS‐TLR4 signaling. The role of LPS‐TLR4 signaling in inducing HCC stemness was further confirmed by tumor xenograft experiment in vivo. Taken together, our findings provide a novel therapeutic target to prevent the recurrence of HCC.

Development and biochemical and immunological characterization of early passage and immortalized bovine intestinal epithelial cell lines from the ileum of a young calf

The intestinal epithelium is a major site of interaction with pathogens. In bovine intestinal epithelial cells (BIECs), Toll-like receptors (TLRs) play an important role in innate immune responses against enteric pathogens. This study is aimed at establishing a stable bovine intestinal epithelial cell line that can be maintained by a continuous passage so that studies on innate immune responses against various enteric pathogens can be performed. The main goal was to establish pure cultures of primary and immortalized bovine intestinal epithelial cells from the ileum and then characterize them biochemically and immunologically. Mixed epithelial and fibroblast bovine ileal intestinal cultures were first established from a 2-day old calf. Limiting dilution method was used to obtain a clone of epithelial cells which was characterized using immunocytochemistry (ICC). The selected clone BIEC-c4 was cytokeratin positive and expressed low levels of vimentin, confirming the epithelial cell phenotype. Early passage BIEC-c4 cells were transfected with either simian virus 40 (SV40) large T antigen or human telomerase reverse transcriptase (hTERT), or human papillomavirus (HPV) type 16E6/E7 genes to establish three immortalized BIEC cell lines. The expression of SV40, hTERT and HPV E6/E7 genes in immortalized BIECs was confirmed by a polymerase chain reaction (PCR). Immunocytochemistry and immunofluorescence assays also confirmed the expression of SV40, hTERT and HPV E6 proteins. The immortalized BIECs were cytokeratin positive and all except HPV-BIECs expressed low levels of vimentin. A growth kinetics study indicated that there were no significant differences in the doubling time of immortalized BIECs as compared to early passage BIEC-c4 cells. All four BIEC types expressed TLR 1-10 genes, with TLR 3 and 4 showing higher expression across all cell types. These newly established early passage and immortalized BIEC cell lines should serve as a good model for studying infectivity, pathogenesis and innate immune responses against enteric pathogens.

Receptors and Signaling Pathways for Recognition of Bacteria in Livestock and Crops: Prospects for Beneficial Microbes in Healthy Growth Strategies

Modern animal and crop production practices are associated with the regular use of antimicrobials, potentially increasing selection pressure on bacteria to become resistant. Alternative approaches are needed in order to satisfy the demands of the growing human population without the indiscriminate use of antimicrobials. Researchers have brought a different perspective to solve this problem and have emphasized the exploitation of animal- and plant-associated microorganisms that are beneficial to their hosts through the modulation of the innate immune system. There is increasing evidence that plants and animals employ microbial perception and defense pathways that closely resemble each other. Formation of pattern recognition receptor (PRR) complexes involving leucine-rich repeat (LRR)-containing proteins, mitogen-activated protein kinase (MAPK)-mediated activation of immune response genes, and subsequent production of antimicrobial products and reactive oxygen species (ROS) and nitric oxide (NO) to improve defenses against pathogens, add to the list of similarities between both systems. Recent pioneering work has identified that animal and plant cells use similar receptors for sensing beneficial commensal microbes that are important for the maintenance of the host's health. Here, we reviewed the current knowledge about the molecular mechanisms involved in the recognition of pathogenic and commensal microbes by the innate immune systems of animal and plants highlighting their differences and similarities. In addition, we discuss the idea of using beneficial microbes to modulate animal and plant immune systems in order to improve the resistance to infections and reduce the use of antimicrobial compounds.

Saccharomyces cerevisiae var. boulardii CNCM I-1079 and Lactobacillus acidophilus BT1386 influence innate immune response and serum levels of acute-phase proteins during weaning in Holstein calves

The aims of this study were to investigate the effect of Saccharomyces cerevisiae var. boulardii CNCM I-1079 (SCB) or Lactobacillus acidophilus BT1386 (LA) on (1) innate immune response, (2) markers of acute-phase reaction, and (3) immune gene expression of rumen and ileum tissues of Holstein calves. Forty eight calves (∼5 d old) were randomly allocated to four treatments as follows: (1) control (CTRL) fed milk replacer followed by starter feed, (2) CTRL supplemented with SCB in milk and feed, (3) CTRL supplemented with LA in milk and feed, and (4) CTRL supplemented with antibiotics (ATB; chlortetracycline and neomycin in milk, and chlortetracycline in feed). Tumor necrosis factor α (TNF-α) decreased (P < 0.05) on day 66 (post-weaning) for the ATB-treated calves. There were no treatment effects on production of interferon γ (IFN-γ) and interleukin 6 (IL-6) proteins and on expression of TLR4, TLR6, TLR9, TLR10, CLDN3, MUC1, and MUC20 genes. Calves fed SCB or LA had a greater (P < 0.05) oxidative burst at weaning (day 53) compared with CTRL. Oxidative burst was also greater (P < 0.05) after weaning (day 59 and day 87) for SCB-fed calves. Calves fed SCB and ATB had higher (P < 0.05) phagocytosis activity during weaning (day 47) compared with CTRL. The concentration of serum amyloid A2 (SAA2) increased (P < 0.05) in SCB- and LA-fed calves (day 53), whereas the concentration of C-reactive protein (CRP) increased (P < 0.05) in SCB-fed calves during weaning as compared with CTRL. Our results suggest that SCB could improve innate immune response (oxidative burst and phagocytosis) and markers of acute-phase reaction (CRP and SAA2), especially during critical periods like weaning.

Antidiarrheal Action of Bacillus subtilis CU1 CNCM I-2745 and Lactobacillus plantarum CNCM I-4547 in Mice

Preventive actions of probiotics as antidiarrheal agents are well documented, but their mechanisms are poorly understood. Two selected probiotics, Bacillus subtilis CU1 and Lactobacillus plantarum CNCM I-4547, were tested in mouse experimental models of diarrhea and the possible mechanisms of action were investigated. Diarrhea was induced in mice by oral castor oil administration or by i.v. injection of lipopolysaccharide (LPS) of Salmonella enteritis. The antidiarrheal drug loperamide was used as control. Fecal water excretion was quantified for 2 h and paracellular permeability and electrical parameters of the colon were assessed in Ussing chambers. The expression of colonic exchangers or channels and of Toll-like receptor 4 (TLR4) was assessed by immunohistochemistry. Prophylactic treatment with B. subtilis CU1 or with L. plantarum CNCM I-4547 reduced LPS-induced diarrhea. The reduction of water excretion was in the same range as those induced by loperamide. In the castor oil model, this effect was only observed with B. subtilis CU1. The two probiotic treatments abolished the increase in paracellular permeability induced by LPS, but not by castor oil. However, only L. plantarum CNCM I-4547 treatment decreased the colonic expression of TLR-4. After B. subtilis CU1, colonic expression of cystic fibrosis transmembrane conductance regulator (CFTR) was reduced and that of Na⁺/H⁺ exchanger 3 (NHE3) increased. B. subtilis CU1 may increase the capacity of the colon to absorb excess of water in diarrheic conditions by acting on CFTR and NHE3 expression. The two probiotics strains showed an impact on diarrhea through limitation of water excretion that may involve paracellular permeability or electrolyte transport for L. plantarum CNCM I-4547 and B. subtilis CU1 respectively.

Early feed restriction of lambs modifies ileal epimural microbiota and affects immunity parameters during the fattening period

Bacteria firmly attached to the gastrointestinal epithelium during the pre-weaning phase may show a significant impact on nutrient processing, immunity parameters, health and feed efficiency of lambs during post-weaning phases. Thus, the aim of this study was to describe the differences in the ileal epimural microbiota (e.g. total bacteria, Prevotella spp., Bifidobacterium spp. and Lactobacillus spp.) of fattening lambs promoted by early feed restriction during the suckling phase trying to elucidate some of the underlying mechanisms behind changes in feed efficiency during the fattening period. A total of 24 Merino lambs (average BW 4.81±0.256 kg) were used, 12 of them (ad libitum, ADL) kept permanently in individual pens with their mothers, whereas the other 12 lambs were separated from their dams for 9 h each day to be exposed to milk restriction (RES). After weaning (BW=15 kg) all the animals were penned individually, offered the same complete pelleted diet (35 g/kg BW per day) and slaughtered at a BW of 27 kg. During the fattening period, reduced gain : feed ratio (0.320 v. 0.261, P<0.001) was observed for the RES group. Moreover, increments of Prevotella spp. were detected in the ileal epimural microbiota of RES lambs (P<0.05). There were also higher numbers of infiltrated lymphocytes (T and B cells) in the ileal lamina propria (P<0.05), a higher M-cell labelling intensity in ileal Peyer's patches domes (P<0.05) and a trend towards a thickening of the submucosa layer when compared with the ADL group (P=0.057). Some other immunological parameters, such as an increased immunoglobulin A (IgA) production (pg IgA/µg total protein) and increments in CD45+ cells were also observed in the ileum of RES group (P<0.05), whereas transforming growth factor β and toll-like receptor gene expression was reduced (P<0.05). In conclusion, early feed restriction during the suckling phase promoted changes in ileal epimural microbiota and several immunity parameters that could be related to differences in feed efficiency traits during the fattening period of Merino lambs.

Innate immune responses induced by lipopolysaccharide and lipoteichoic acid in primary goat mammary epithelial cells

Background

Innate immune responses induced by in vitro stimulation of primary mammary epithelial cells (MEC) using Gram-negative lipopolysaccharide (LPS) and Gram-positive lipoteichoic acid (LTA) bacterial cell wall components are well- characterized in bovine species. The objective of the current study was to characterize the downstream regulation of the inflammatory response induced by Toll-like receptors in primary goat MEC (pgMEC). We performed quantitative real-time RT-PCR (qPCR) to measure mRNA levels of 9 genes involved in transcriptional regulation or antibacterial activity: Toll-like receptor 2 (TLR2), Toll-like receptor 4 (TLR4), prostaglandin-endoperoxide synthase 2 (PTGS2), interferon induced protein with tetratricopeptide repeats 3 (IFIT3), interferon regulatory factor 3 (IRF3), myeloid differentiation primary response 88 (MYD88), nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1), Toll interacting protein (TOLLIP), and lactoferrin (LTF). Furthermore, we analyzed 7 cytokines involved in Toll-like receptor signaling pathways: C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 5 (CCL5), C-X-C motif chemokine ligand 6 (CXCL6), interleukin 8 (CXCL8), interleukin 1 beta (IL1B), interleukin 6 (IL6), and tumor necrosis factor alpha (TNF).

Results

Stimulation of pgMEC with LPS for 3 h led to an increase in expression of CCL2, CXCL6, IL6, CXCL8, PTGS2, IFIT3, MYD88, NFKB1, and TLR4 (P < 0.05). Except for IL6, and PTGS2, the same genes had greater expression than controls at 6 h post-LPS (P < 0.05). Expression of CCL5, PTGS2, IFIT3, NFKB1, TLR4, and TOLLIP was greater than controls after 3 h of incubation with LTA (P < 0.05). Compared to controls, stimulation with LTA for 6 h led to greater expression of PTGS2, IFIT3, NFKB1, and TOLLIP (P < 0.05) whereas the expression of CXCL6, CXCL8, and TLR4 was lower (P < 0.05). At 3 h incubation with both toxins compared to controls a greater expression (P < 0.05) of CCL2, CCL5, CXCL6, CXCL8, IL6, PTGS2, IFIT3, IRF3, MYD88, and NFKB1 was detected. After 6 h of incubation with both toxins, the expression of CCL2, CXCL6, IFIT3, MYD88, NFKB1, and TLR4 was higher than the controls (P < 0.05).

Conclusions

Data indicate that in the goat MEC, LTA induces a weaker inflammatory response than LPS. This may be related to the observation that gram-positive bacteria cause chronic mastitis more often than gram-negative infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s40104-017-0162-8) contains supplementary material, which is available to authorized users.

Applications of Genetically Modified Immunobiotics with High Immunoregulatory Capacity for Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn’s disease, are chronic inflammatory diseases characterized by dysregulated immune responses of the gastrointestinal tract. In recent years, the incidence of IBDs has increased in developed nations, but their prophylaxis/treatment is not yet established. Site-directed delivery of molecules showing anti-inflammatory properties using genetically modified (gm)-probiotics shows promise as a new strategy for the prevention and treatment of IBD. Advantages of gm-probiotics include (1) the ability to use bacteria as a delivery vehicle, enabling safe and long-term use by humans, (2) decreased risks of side effects, and (3) reduced costs. The intestinal delivery of anti-inflammatory proteins such as cytokines and enzymes using Lactococcus lactis has been shown to regulate host intestinal homeostasis depending on the delivered protein-specific machinery. Additionally, clinical experience using interleukin 10-secreting Lc. lactis has been shown to be safe and to facilitate biological containment in IBD therapy. On the other hand, some preclinical studies have demonstrated that gm-strains of immunobiotics (probiotic strains able to beneficially regulate the mucosal immunity) provide beneficial effects on intestinal inflammation as a result of the synergy between the immunoregulatory effects of the bacterium itself and the anti-inflammatory effects of the delivered recombinant proteins. In this review, we discuss the rapid progression in the development of strategies for the prophylaxis and treatment of IBD using gm-probiotics that exhibit immune regulation effects (gm-immunobiotics). In particular, we discuss the type of strains used as delivery agents.

Lactobacillus rhamnosus GG modulates innate signaling pathway and cytokine responses to rotavirus vaccine in intestinal mononuclear cells of gnotobiotic pigs transplanted with human gut microbiota

Background

A better understanding of mechanisms underlying dose-effects of probiotics in their applications as treatments of intestinal infectious or inflammatory diseases and as vaccine adjuvant is needed. In this study, we evaluated the modulatory effects of Lactobacillus rhamnosus GG (LGG) on transplanted human gut microbiota (HGM) and on small intestinal immune cell signaling pathways in gnotobiotic pigs vaccinated with an oral attenuated human rotavirus (AttHRV) vaccine.

Results

Neonatal HGM transplanted pigs were given two doses of AttHRV on 5 and 15 days of age and were divided into three groups: none-LGG (AttHRV), 9-doses LGG (AttHRV + LGG9X), and 14-doses LGG (AttHRV + LGG14X) (n = 3–4). At post-AttHRV-inoculation day 28, all pigs were euthanized and intestinal contents and ileal tissue and mononuclear cells (MNC) were collected. AttHRV + LGG14X pigs had significantly increased LGG titers in the large intestinal contents and shifted structure of the microbiota as indicated by the formation of a cluster that is separated from the cluster formed by the AttHRV and AttHRV + LGG9X pigs. The increase in LGG titers concurred with significantly increased ileal HRV-specific IFN-γ producing T cell responses to the AttHRV vaccine reported in our previous publication, suggesting pro-Th1 adjuvant effects of the LGG. Both 9- and 14-doses LGG fed pig groups had significantly higher IkBα level and p-p38/p38 ratio, while significantly lower p-ERK/ERK ratio than the AttHRV pigs, suggesting activation of regulatory signals during immune activation. However, 9-doses, but not 14-doses LGG fed pigs had enhanced IL-6, IL-10, TNF-α, TLR9 mRNA levels, and p38 MAPK and ERK expressions in ileal MNC. Increased TLR9 mRNA was in parallel with higher mRNA levels of cytokines, p-NF-kB and higher p-p38/p38 ratio in MNC of the AttHRV + LGG9X pigs.

Conclusions

The relationship between modulation of gut microbiota and regulation of host immunity by different doses of probiotics is complex. LGG exerted divergent dose-dependent effects on the intestinal immune cell signaling pathway responses, with 9-doses LGG being more effective in activating the innate immunostimulating TLR9 signaling pathway than 14-doses in the HGM pigs vaccinated with AttHRV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0727-2) contains supplementary material, which is available to authorized users.

Lactic acid bacteria: reviewing the potential of a promising delivery live vector for biomedical purposes

Lactic acid bacteria (LAB) have a long history of safe exploitation by humans, being used for centuries in food production and preservation and as probiotic agents to promote human health. Interestingly, some species of these Gram-positive bacteria, which are generally recognized as safe organisms by the US Food and Drug Administration (FDA), are able to survive through the gastrointestinal tract (GIT), being capable to reach and colonize the intestine, where they play an important role. Besides, during the last decades, an important effort has been done for the development of tools to use LAB as microbial cell factories for the production of proteins of interest. Given the need to develop effective strategies for the delivery of prophylactic and therapeutic molecules, LAB have appeared as an appealing option for the oral, intranasal and vaginal delivery of such molecules. So far, these genetically modified organisms have been successfully used as vehicles for delivering functional proteins to mucosal tissues in the treatment of many different pathologies including GIT related pathologies, diabetes, cancer and viral infections, among others. Interestingly, the administration of such microorganisms would suppose a significant decrease in the production cost of the treatments agents since being live organisms, such vectors would be able to autonomously amplify and produce and deliver the protein of interest. In this context, this review aims to provide an overview of the use of LAB engineered as a promising alternative as well as a safety delivery platform of recombinant proteins for the treatment of a wide range of diseases.