Microbial products from probiotic bacteria inhibit Salmonella enteritidis 857-induced IL-8 synthesis in Caco-2 cells

Pediococcus acidilactici isolated from traditional cheese as a potential probiotic with cytotoxic activity against doxorubicin-resistant MCF-7 cells

The considerable flexibility of cancerous cells to escape from chemical and biological drugs makes it clear that much is to be done to control and eliminate such cells. Probiotic bacteria, in this regard, have shown promising performance. In this study, we isolated and characterized lactic acid bacteria from traditional cheese. Then we evaluated their activity against doxorubicin-resistant MCF-7 cells (MCF-7/DOX) through MTT assay, Annexin V/PI protocol, real-time PCR, and western blotting. Among the isolates, one strain with more than 97% similarity with Pediococcus acidilactici showed considerable probiotics properties. Low pH, high bile salts, and NaCl could not significantly affect this strain while it was susceptible to antibiotics. Also, it had a potent antibacterial activity. Besides, the cell-free supernatant of this strain (CFS) significantly reduced the viability of MCF-7 and MCF-7/DOX cancerous cells (to about 10% and 25%, respectively), while it was safe for normal cells. Also, we found that CFS could regulate the Bax/Bcl-2 at mRNA and protein levels to induce apoptosis in drug-resistant cells. We determined 75% early apoptosis, 10% late apoptosis, and 15% necrosis in the cells treated with the CFS. These findings can accelerate the development of probiotics as promising alternative treatments to overcome drug-resistant cancers.

Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk reduce chemokine IL-8 production in response to TNF-α in Caco-2 cell line, an exploratory study

Streptococci are a predominant genera of the human milk microbiome. Among different lactic acid bacteria (LAB) a few Streptococcal strains are also considered as probiotics. Probiotic bacteria are reported to modulate immunity when consumed in adequate amount and bacterial hydrophobicity can be considered as a preliminary experiment for the adhesive capability of probiotic bacteria to the epithelial cells. The present study aimed to investigate the probiotic, hydrophobic and immune modulation property of Streptococcus lactarius MB622 and Streptococcus salivarius MB620, isolated from human milk. S. lactarius MB622 and S. salivarius MB620 displayed higher hydrophobicity (78 % and 59 % respectively) in addition to intrinsic probiotic properties such as gram positive classification, catalase negative activity, resistance to artificially stimulated gastric juice and gastrointestinal bile salt concentration. In conclusion Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk when administered in sufficient amount and for certain duration could be used to reduce inflammation inside the colon by reducing the production of inflammatory booster (IL-8) in diseased state.

Lactiplantibacillus plantarum 299v (LP299V®): three decades of research

This review aims to provide a comprehensive overview of the in vitro, animal, and clinical studies with the bacterial strain Lactiplantibacillus plantarum 299v (L. plantarum 299v; formerly named Lactobacillus plantarum 299v) published up until June 30, 2020. L. plantarum 299v is the most documented L. plantarum strain in the world, described in over 170 scientific publications out of which more than 60 are human clinical studies. The genome sequence of L. plantarum 299v has been determined and is available in the public domain (GenBank Accession number: NZ_LEAV01000004). The probiotic strain L. plantarum 299v was isolated from healthy human intestinal mucosa three decades ago by scientists at Lund University, Sweden. Thirty years later, a wealth of data coming from in vitro, animal, and clinical studies exist, showing benefits primarily for gastrointestinal health, such as reduced flatulence and abdominal pain in patients with irritable bowel syndrome (IBS). Moreover, several clinical studies have shown positive effects of L. plantarum 299v on iron absorption and more recently also on iron status. L. plantarum 299v is safe for human consumption and does not confer antibiotic resistance. It survives the harsh conditions of the human gastrointestinal tract, adheres to mannose residues on the intestinal epithelial cells and has in some cases been re-isolated more than ten days after administration ceased. Besides studying health benefits, research groups around the globe have investigated L. plantarum 299v in a range of applications and processes. L. plantarum 299v is used in many different food applications as well as in various dietary supplements. In a freeze-dried format, L. plantarum 299v is robust and stable at room temperature, enabling long shelf-lives of consumer healthcare products such as capsules, tablets, or powder sachets. The strain is patent protected for a wide range of indications and applications worldwide as well as trademarked as LP299V^®.

Interleukin-8 gene expression and apoptosis induced by Salmonella Typhimurium in the presence of Bacillus probiotics in the epithelial cell

AIMS

This study aimed to evaluate the effects of three Bacillus probiotics on Salmonella Typhimurium, and interleukin-8 (IL-8) gene expression in the co-culture of the Bacillus and the pathogen in vitro.

METHODS AND RESULTS

Bacillus subtilis, Bacillus indicus and Bacillus coagulans were initially turned to spore and heat-inactivated forms. The cellular damages of the probiotics on the HT-29 cells were investigated individually and in combination with S. Typhimurium using 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and fluorescence assays. To extract cell free supernatants (CFS) of the probiotics, they were cultured in selective media. The inhibitory activity of CFSs were then assayed against the pathogen. The gene expression of IL-8 of the HT-29 cells was evaluated by real-time PCR in all the groups. The results showed that the CFSs of three probiotics could inhibit the growth of S. Typhimurium by more than 50%. Inhibitory effects of B. indicus and B. subtilis CFSs were related to the production of pepsin-sensitive compounds, except B. coagulans in which the high inhibitory effect was due to organic acids. The spores of the three probiotics and the heat-inactivated forms of B. subtilis and B. coagulans could reduce the cytotoxicity of S. Typhimurium. The cell viability also increased applying both forms probiotics against the pathogen. In all co-culture groups, the IL-8 gene expression induced by S. Typhimurium was reduced.

CONCLUSIONS

The three Bacillus probiotics can be considered as proper candidates for the prevention and treatment of S. Typhimurium food poisoning.

SIGNIFICANCE AND IMPACT OF THE STUDY

Applying probiotics as live bacteria is universally noted in foods. This study tried to discover the effects of Bacillus probiotics in the form of spore or even heat-killed bacteria against S. Typhimurium and evaluate ratio of IL-8 gene expression in cell culture. The most effective Bacillus probiotic will be recommended. This approach will help to use probiotics as nonvegetative cells in foods to fight gastrointestinal pathogens.

Effects of Lactobacillus rhamnosus GG and Escherichia coli Nissle 1917 Cell-Free Supernatants on Modulation of Mucin and Cytokine Secretion on Human Intestinal Epithelial HT29-MTX Cells

This study examined modulation effects of cell-free supernatants of two commonly studied probiotic bacteria Lactobacillus rhamnosus GG (LGG) and Escherichia coli Nissle 1917 (EcN) on mucin and cytokine profiles of human intestinal epithelial HT29-MTX cells. It was found that LGG and EcN supernatants differentially modulated MUC5AC and MUC5B mRNA and protein, and total mucin-like glycoprotein secretion. Regarding modulation of cytokine profiles, LGG supernatants moderately influenced the secretion of anti-inflammatory cytokines such as interleukin (IL)-4, IL-5, and IL-10, while those of EcN exerted a broad proinflammatory effect to intestinal epithelial cells by inducing the secretion of proinflammatory cytokines such as IL-8, monocyte chemotactic protein-1, transforming growth factor α, tumor necrosis factor α, granulocyte macrophage colony-stimulating factor, and interferon γ. These results suggested that LGG and EcN might produce different bioactive products that display differential modulation of mucin and cytokines, which may contribute to intestinal health and/or defense against bacteria/pathogens.

PRACTICAL APPLICATION

The results suggested that LGG and EcN might produce different bioactive products that display differential modulation of mucin and cytokines, which may contribute to intestinal health and/or defense against bacteria/pathogens.

Anti-infective activities of lactobacillus strains in the human intestinal microbiota: from probiotics to gastrointestinal anti-infectious biotherapeutic agents

A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from which Lactobacillus probiotic strains have often been isolated. Only six probiotic Lactobacillus strains isolated from human intestinal microbiota, i.e., L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probiotic Lactobacillus strains. What is known about the antimicrobial activities supported by the molecules secreted by such probiotic Lactobacillus strains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract.

Contribution of microbiota to the intestinal physicochemical barrier

The large number of intestinal microorganisms, which exceeds the total number of human cells by ten folds, alludes to a significant contribution to human health. This is vivid in enteric and some systemic diseases emanating from disruption of the microbiota. As life style keeps shifting towards disruption of the microbiota in most societies worldwide, interest in the contribution of the microbiota to gut health has grown enormously. Many studies have been conducted to elucidate the exact contribution of the microbiota to human health. The knowledge gained from these studies indicates that the microbiota interacts with the intestinal milieu to maintain gut health. In this review, the crosstalk of microbiota with the intestinal physicochemical barrier pivotal to the gut innate immunity is highlighted. In particular, the review focuses on the role of the microbiota on competitive exclusion of pathogens, intestinal pH, epithelial mechanical barrier integrity, apical actin cytoskeleton, antimicrobial peptides, and the mucus layer. Understanding this microbe-host relationship will provide useful insight into overcoming some diseases related to the disruption of the host microbiota.

Gut epithelial inducible heat-shock proteins and their modulation by diet and the microbiota

The epidemic of metabolic diseases has raised questions about the interplay between the human diet and the gut and its microbiota. The gut has two vital roles: nutrient absorption and intestinal barrier function. Gut barrier defects are involved in many diseases. Excess energy intake disturbs the gut microbiota and favors body entry of microbial compounds that stimulate chronic metabolic inflammation. In this context, the natural defense mechanisms of gut epithelial cells and the potential to boost them nutritionally warrant further study. One such important defense system is the activation of inducible heat-shock proteins (iHSPs) which protect the gut epithelium against oxidative stress and inflammation. Importantly, various microbial components can induce the expression of iHSPs. This review examines gut epithelial iHSPs as the main targets of microbial signals and nutrients and presents data on diseases involving disturbances of gut epithelial iHSPs. In addition, a broad literature analysis of dietary modulation of gut epithelial iHSPs is provided. Future research aims should include the identification of gut microbes that can optimize gut-protective iHSPs and the evaluation of iHSP-mediated health benefits of nutrients and food components.

Lactobacillus acidophilus attenuates Salmonella-induced intestinal inflammation via TGF-β signaling

BACKGROUND

Salmonella is a common intestinal pathogen that causes acute and chronic inflammatory response. Probiotics reduce inflammatory cytokine production and serve as beneficial commensal microorganisms in the human gastrointestinal tract. TGF-β (transforming growth factor β)/SMAD and NF-κB signaling play important roles in inflammation in intestinal cells. However, the involvement of the signaling in regulating inflammation between Salmonella and probiotics is not fully understood.

METHODS

L. acidophilus and prebiotic inulin were used to treat human intestinal Caco-2 cells prior to infection with Salmonella. The cells were harvested to examine the cytokines and MIR21 expression with immunoblotting and real-time PCR. NF-κB and SMAD3/4 reporter vectors were transfected into cells to monitor inflammation and TGF-β1 signaling, respectively.

RESULTS

In this study, we showed that the probiotic L. acidophilus decreased Salmonella-induced NF-κB activation in human intestinal Caco-2 cells. Expression of the inflammatory cytokines, TNF-α and IL-8, in L. acidophilus-pretreated cells was also significantly lower than that in cells infected with Salmonella alone. Moreover, TGF-β1 and MIR21 expression was elevated in cells pretreated with L. acidophilus or synbiotic, a combination of inulin and L. acidophilus, compared to that in untreated cells or cells infected with S. typhimurium alone. By contrast, expression of SMAD7, a target of MIR21, was accordingly reduced in cells treated with L. acidophilus or synbiotics. Consistent with TGF-β1/MIR21 and SMAD7 expression, SMAD3/4 transcriptional activity was significantly higher in the cells treated with L. acidophilus or synbiotics. Furthermore, TGF-β1 antibody antagonized the SMAD3/4 and NF-κB transcriptional activity modulated by L. acidophilus in intestinal cells.

CONCLUSION

Our results suggest that the TGF-β1/MIR21 signaling pathway may be involved in the suppressive effects of L. acidophilus on inflammation caused by S. typhimurium in intestinal Caco-2 cells.

Effects of probiotic intake and gender on nontyphoid Salmonella infection

GOALS

The goal of the study was to examine if intake of Lactobacillus plantarum can accelerate clearance of nontyphoid Salmonella and reduce infection-related symptoms.

BACKGROUND

Nontyphoid Salmonella is a major cause of gastroenteritis worldwide. Few studies have explored the effect of probiotics in these infections.

STUDY

Patients with Salmonella infection were randomized to daily intake of 5 × 10 colony forming units of freeze-dried Lactobacillus plantarum 299 v or placebo. Symptoms were recorded daily. Feces were cultured weekly. Treatment continued until 4 consecutive stool cultures negative for Salmonella had been obtained.

RESULTS

The treatment and placebo groups did not differ significantly with regard to time to clearance of Salmonella, or time to resolution of symptoms. Irrespective of treatment, women tended to clear Salmonella more rapidly than men (19 vs. 28 d, P=0.18), despite a longer diarrheal phase (5 vs. 3 days after inclusion, P=0.001). After Salmonella clearance (postinfectious phase), women experienced loose stools, nausea, and flatulence more frequently than men. In women, L. plantarum treatment was associated with more abdominal pain, whereas in men L. plantarum treatment reduced the prevalence of hard stools, and increased the presence of diarrheal symptoms in the postinfectious phase.

CONCLUSIONS

Gender, but not administration of the probiotic strain L. plantarum 299 v, may influence acute symptoms during Salmonella infection and possibly clearance of Salmonella. Symptoms in the postinfectious phase were modified by the probiotics in a gender-specific way, but our results give little support for positive effects of L. plantarum 299 v treatment in nontyphoid salmonellosis.

Lactobacillus plantarum 2142 prevents intestinal oxidative stress in optimized in vitro systems

Recently, there has been a growing interest to replace antibiotics' administration with the application of probiotics. The aim of our investigations was to reveal the influence of spent culture supernatant of Lactobacillus plantarum 2142 on the response of enterocytes to oxidative stress, and the spent culture supernatant's ability to protect them from oxidative injury. The experiments were performed on non-carcinogenic porcine epithelial cell line, IPEC-J2 isolated from a neonatal piglet and on human colon adenocarcinoma cell line, Caco-2. The cells cultured on membrane inserts were treated with millimolar hydrogen peroxide solution to provoke oxidative stress. The peroxide-triggered cell response profile was evaluated via determination of change in transepithelial electrical resistance, quantification of extent of cell death by 4',6-diamidino-2 phenylindole (DAPI) staining and via estimation of proinflammatory cytokine, IL-8 production using ELISA technique. Non-starter lactobacilli supernatant-mediated inhibition of peroxide-triggered upregulation of IL-8 production confirmed the antiinflammatory properties of active metabolites produced by Lactobacillus plantarum 2142 in acute oxidative stress.

Lactobacilli reduce chemokine IL-8 production in response to TNF-α and Salmonella challenge of Caco-2 cells

The probiotic properties of two selected lactobacilli strains were assessed. L. salivarius and L. plantarum displayed higher hydrophobicity (48% and 54%, resp.) and coaggregation ability with four pathogens (from 7.9% to 57.5%). L. salivarius and L. plantarum had good inhibitory effects on S. aureus (38.2% and 49.5%, resp.) attachment to Caco-2 cells. Live lactobacilli strains and their conditioned media effectively inhibited IL-8 production (<14.6 pg/mL) in TNF-α-induced Caco-2 cells. Antibiotic-treated and the sonicated lactobacilli also maintained inhibitory effects (IL-8 production from 5.0 to 36.3 pg/mL); however, the heat-treated lactobacilli lost their inhibitory effects (IL-8 production from 130.2 to 161.0 pg/mL). These results suggest that both the structural components and the soluble cellular content of lactobacilli have anti-inflammatory effects. We also found that pretreatment of Caco-2 cells with lactobacilli inhibited S. typhimurium-induced IL-8 production (<27.3 pg/mL). However, lactobacilli did not inhibit IL-8 production in Caco-2 cells pretreated with S. typhimurium. These results suggest that the tested lactobacilli strains are appropriate for preventing inflammatory diseases caused by enteric pathogens but not for therapy. In short, L. salivarius and L. plantarum are potential candidates for the development of microbial ecological agents and functional foods.

Compound(s) secreted by Lactobacillus casei strain Shirota YIT9029 irreversibly and reversibly impair the swimming motility of Helicobacter pylori and Salmonella enterica serovar Typhimurium, respectively

We conducted experiments in order to examine whether the probiotic Lactobacillus casei strain Shirota YIT9029 (LcS) in vitro and in vivo antagonism of Helicobacter pylori and Salmonella, involves inhibition of the swimming motility of these pathogens. We report the irreversible inhibition of the swimming motility of H. pylori strain 1101 and reversible inhibition of Salmonella enterica serovar Typhimurium (S. Typhimurium) strain SL1344 by compound(s) secreted by LcS. In H. pylori 1101, irreversible inhibition results in the helical cells being progressively replaced by cells with 'c'-shaped and coccoid morphologies, accompanied by a loss of FlaA and FlaB flagellin expression. In S. Typhimurium SL1344, transient inhibition develops after membrane depolarization and without modification of expression of FliC flagellin. The inhibitory activity of strain LcS against both S. Typhimurium and H. pylori swimming motilities is linked with a small sized, heat-sensitive, and partially trypsin-sensitive, secreted compound(s), and needed the cooperation of the secreted membrane permeabilizing lactic acid metabolite. The inhibition of S. Typhimurium SL1344 swimming motility leads to delayed cell entry into human enterocyte-like Caco-2/TC7 cells and a strong decrease of cell entry into human mucus-secreting HT29-MTX cells.

Gut microbiota imbalance and chaperoning system malfunction are central to ulcerative colitis pathogenesis and can be counteracted with specifically designed probiotics: a working hypothesis

In this work, we propose that for further studies of the physiopathology and treatment for inflammatory bowel diseases, an integral view of the conditions, including the triad of microbiota-heat shock proteins (HSPs)-probiotics, ought to be considered. Microbiota is the complex microbial flora that resides in the gut, affecting not only gut functions but also the health status of the whole body. Alteration in the microbiota's composition has been implicated in a variety of pathological conditions (e.g., ulcerative colitis, UC), involving both gut and extra-intestinal tissues and organs. Some of these pathologies are also associated with an altered expression of HSPs (chaperones) and this is the reason why they may be considered chaperonopathies. Probiotics, which are live microorganisms able to restore the correct, healthy equilibrium of microbiota composition, can ameliorate symptoms in patients suffering from UC and modulate expression levels of HSPs. However, currently probiotic therapy follows ex-adiuvantibus criteria, i.e., treatments with beneficial effects but whose mechanism of action is unknown, which should be changed so the probiotics needed in each case are predetermined on the basis of the patient's microbiota. Consequently, efforts are necessary to develop diagnostic tools for elucidating levels and distribution of HSPs and the microbiota composition (microbiota fingerprint) of each subject and, thus, guide specific probiotic therapy, tailored to meet the needs of the patient. Microbiota fingerprinting ought to include molecular biology techniques for sequencing highly conserved DNA, e.g., genes encoding 16S RNA, for species identification and, in addition, quantification of each relevant microbe.

Metabolites of Lactobacillus plantarum 2142 prevent oxidative stress-induced overexpression of proinflammatory cytokines in IPEC-J2 cell line

Probiotics have already proven beneficial effects in the treatment of several intestinal infections, but the underlying mechanisms how the probiotics can affect responses of porcine IPEC-J2 enterocytes to oxidative stress remained to be elucidated. The immunomodulatory effect of five bacterial strains (Lactobacillus plantarum 2142, Lactobacillus casei Shirota, Bifidobacterium animalis subsp. lactis BB-12, Bacillus amyloliquefaciens CECT 5940 and Enterococcus faecium CECT 4515) on 1 mM peroxide-triggered upregulation of interleukin (IL)-8 and tumor necrosis factor alpha (TNF-α) level was screened by q RT-PCR. Our data revealed that spent culture supernatant (SCS) of L. plantarum 2142 had significant lowering effect on IL-8 and TNF-α level with concomitant promoting activity on protective Hsp70 gene expression. According to our results, lactic acid (racemic, D: - and L: -lactic acid) and acetic acid produced by lactobacilli had no protective effect in quenching upregulation of proinflammatory cytokines. Furthermore, L. plantarum 2142-specific supernatant peptides were detected by gel electrophoresis and capillary zone electrophoresis.