Human-origin Lactobacillus salivarius AR809 protects against immunosuppression in S. aureus-induced pharyngitis via Akt-mediated NF-κB and autophagy signaling pathways

Jiegeng decoction ameliorated acute pharyngitis through suppressing NF-κB and MAPK signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Jiegeng decoction (JGD), consisting of Glycyrrhizae Radix et Rhizoma and Platycodonis Radix at the ratio of 2:1, is a classical Chinese medicine prescription firstly recorded in "Treatise on Febrile Diseases". JGD has been extensively utilized to treat sore throat and lung diseases for thousands of years in China. However, the pharmacological effect and mechanism of JGD on acute pharyngitis (AP) remain unclear.

AIM OF THE STUDY

Our research aimed to reveal the pharmacological effect of JGD on AP and its potential mechanisms.

MATERIALS AND METHODS

The chemical components of JGD were analyzed based on the UPLC-MS analysis. The anti-inflammatory effect of JGD was evaluated by NO production using the Griess assay in RAW 264.7 cells. The mRNA expression of iNOS, IL-1β, IL-10, TNF-α, IL-6 and MCP-1 was determined by qRT-PCR in vitro. A 15% ammonia-induced AP model was established. The histopathology, the inflammatory cytokines IL-6 and MCP-1 in serum and the apoptosis-related genes caspease-8 and caspease-3 were determined by H&E staining, ELISA and qRT-PCR, respectively. The expression levels of p-p65, p65, p-JNK, JNK, p-p38, p38, p-ERK1/2, ERK1/2, and COX2 were measured through western blotting.

RESULTS

Nine compounds, including liquiritin, liquiritin apiosde, liquiritigenin, platycodin D, platycoside A, licorice saponin J2, licorice saponin G2, glycyrrhizic acid, and licochalcone A, were identified. JGD significantly inhibited NO production and regulated the mRNA expression levels of cytokines in LPS-stimulated RAW 264.7 cells. The results of in vivo experiments confirmed that JGD ameliorated AP through improving the pathological state of pharyngeal tissue, decreasing the serum levels of IL-6 and MCP-1 and preventing the tissue mRNA expression of caspease-8 and caspease-3. Furthermore, JGD also inhibited the NF-κB and MAPK pathways in the AP model.

CONCLUSIONS

This study suggested that JGD could alleviate AP through its anti-inflammation via NF-κB and MAPK pathways, which supported the traditional application of JGD for the treatment of throat diseases.

Metabolites, flavor profiles and ripening characteristics of Monascus-ripened cheese enhanced by Ligilactobacillus salivarius AR809 as adjunct culture

Adjunct cultures strongly determined the distinguishing sensorial and nutritional characteristics of cheeses. Metabolites, flavor profiles and ripening characteristics of Monascus-ripened cheese enhanced by the co-fermentation of Ligilactobacillus salivarius AR809 were investigated. The AR809 significantly increased the contents of soluble nitrogen, small peptides (<1200 Da), free amino acids, and casein degradation degree in the resulting cheese. Furthermore, AR809 significantly promoted the formation of methyl ketones during cheese maturation. Based on untargeted metabolomics analysis, metabolites related to fatty acids metabolism and lysine degradation were highly enriched in Monascus-rich region of cheese. AR809 was primarily engaged in amino acid metabolism, promoting the synthesis of amino acids and dipeptide. L. salivarius and Monascus co-fermentation produced more beneficial bioactive metabolites involved in amino acids and lipid metabolisms than Monascus used alone in cheese ripening. Therefore, as adjunct culture, L. salivarius AR809 exhibited tremendous potential in improving nutrition and flavor quality during cheese ripening.

Therapeutic effect of Hosta plantaginea (Lam.) Aschers flowers on acute pharyngitis through inhibition of multi-inflammatory pathways in rats

BACKGROUND

Hosta plantaginea (Lam.) Aschers flower is a famous Mongolian folk medicine in China and has a therapeutic effect on acute pharyngitis (AP). However, the effect and potential mechanism of H. plantaginea flower on AP have not been fully elucidated.

AIM OF THE STUDY

The present work aimed to evaluate the effects and mechanisms of the crude extract of H. plantaginea flowers (HP) and its four fractions of petroleum ether fraction (HPA), ethyl acetate fraction (HPB), n-butanol fraction (HPC), and water residue (HPD) against AP in rats.

MATERIALS AND METHODS

A 15% ammonia-induced AP rat model in rats was established. Therapeutic effects of HP and HPA∼D in model rats were evaluated based on body weight, histopathological analysis, and inflammatory parameters, including tumor necrosis factor α (TNF-α), prostaglandin E2 (PGE2), interleukin 1β (IL-1β), and IL-6. The protein expression of nuclear factor kappa-B p65 (NF-κB p65), inhibitor of NF-κB alpha (IκBα), c-Jun N-terminal kinases (JNK), mitogen-activated protein kinase (MAPK) p38, extracellular signal-regulated kinase (Erk), just another kinase 1 (JAK1), signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt) were detected by a Western blotting assay.

RESULTS

HP, HPB, and HPC treatments markedly alleviated AP in rats by increasing body weight and improving pathological damages in pharyngeal tissues. In addition, HP, HPB, and HPC treatments significantly inhibited inflammation, including decreasing the levels of TNF-α, PGE2, IL-1β, and IL-6, and suppressing phosphorylated protein expression of p65, IκBα, JNK, p38, Erk, JAK1, STAT3, PI3K, and Akt in pharyngeal tissues of rats.

CONCLUSION

Collectively, HP, HPB, and HPC can attenuate pharynx injury in rats by suppressing inflammation via inhibition of NF-κB, MAPKs, JAK-STAT, and PI3K-Akt pathways, which supports the traditional use of H. plantaginea flowers.

Changes in Intracellular and Extracellular Metabolites of Mixed Lactobacillus Strains Enhance Inhibition of Pathogenic Bacterial Growth and Lipopolysaccharide-Induced Alleviation of RAW264.7 Cellular Inflammation

It is important to explore whether there are antagonistic and synergistic effects between different strains of Lactobacillus when developing mixed Lactobacillus strain products. In this study, we investigated the antagonistic and symbiotic effects of co-cultured Lactobacillus strains, as well as their amelioratory effects on lipopolysaccharide (LPS)-induced inflammation and oxidative stress in RAW264.7 cells. The Lactobacillus strains tested in this paper showed no antagonism. Co-culture of Lactiplantibacillus plantarum Y44 and L. plantarum AKS-WS9 was found to show inhibiting effects on the growth of Escherichia coli and Staphylococcus aureus. Additionally, the co-cultured Lactiplantibacillus plantarum Y44 and L. plantarum AKS-WS9 relieved inflammation in RAW264.7 cells induced by LPS by inhibiting the activation of NF-κB and P38 signaling pathways and down-regulating the expression of pro-inflammatory cytokines NO, ROS, iNOs and TNF-α. And the co-cultured Lactobacillus strains activated the Nrf2 signaling pathway in the LPS-induced RAW264.7 cells to promote the expression of antioxidant enzymes in response to oxidative stress. There was a difference in intracellular and extracellular metabolites between single or co-cultured Lactobacillus strains, and the co-cultured Lactobacillus strains significantly increased extracellular metabolites 4-chlorobenzaldehyde, psoromic acid, and 2-dodecylbenzenesulfonic acid and intracellular metabolites 9(S)-HODE, pyocyanin, and LysoPA. We inferred that the better antibacterial and anti-inflammatory ability of the co-cultured Lactobacillus strains were related to the changes in the metabolites of the co-cultured Lactobacillus strains. The co-cultured L. plantarum Y44 and L. plantarum AKS-WS9 strains exhibited better anti-inflammatory abilities and had the potential to alleviate the symptoms of inflammatory diseases as mixed probiotics.

Influence of Microbiota on Vaccine Effectiveness: "Is the Microbiota the Key to Vaccine-induced Responses?"

Vaccines are one of the most powerful tools for preventing infectious diseases. To effectively fight pathogens, vaccines should induce potent and long-lasting immune responses that are specific to the pathogens. However, not all vaccines can induce effective immune responses, and the responses vary greatly among individuals and populations. Although several factors, such as age, host genetics, nutritional status, and region, affect the effectiveness of vaccines, increasing data have suggested that the gut microbiota is critically associated with vaccine-induced immune responses. In this review, I discuss how gut microbiota affects vaccine effectiveness based on the clinical and preclinical data, and summarize possible underlying mechanisms related to the adjuvant effects of microbiota. A better understanding of the link between vaccine-induced immune responses and the gut microbiota using high-throughput technology and sophisticated system vaccinology approaches could provide crucial insights for designing effective personalized preventive and therapeutic vaccination strategies.

Evaluation of the Potential Protective Effects of Lactobacillus Strains against Helicobacter pylori Infection: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

The beneficial effects of probiotic supplementation standard antibiotic therapies for Helicobacter pylori infection have been verified, but the ability of probiotic monotherapy to eradicate H. pylori remains unclear.

AIM

To evaluate the accuracy and efficacy of specific Lactobacillus strains against H. pylori infection.

METHODS

Seventy-eight patients with H. pylori infection were treated with strain L. crispatus G14-5M (L. crispatus CCFM1118) or L. helveticus M2-09-R02-S146 (L. helveticus CCFM1121) or L. plantarum CCFM8610 at a dose of 2 g twice daily for one month. ¹⁴C-urea breath test, the gastrointestinal symptom rating scale, serum pepsinogen concentrations, and serum cytokine concentrations of patients were measured at baseline and end-of-trial to analyze the effect of the Lactobacillus strains in eradicating H. pylori infection and reducing gastrointestinal discomfort in patients. In addition, the composition and abundance of the intestinal microbiota of patients were also measured at end-of-trial.

RESULTS

The ¹⁴C-urea breath test value of the three Lactobacillus treatment groups had decreased significantly, and the eradication rate of H. pylori had increased by the end of the trial. In particular, the eradication rate in the G14-5M treatment group was significantly higher than the placebo group (70.59% vs. 15.38%, P=0.0039), indicating that one-month administration of the G14-5M regimen was sufficient to eradicate H. pylori infection. The ingestion of Lactobacillus strains also ameliorated the gastrointestinal symptom rating scale scores, and the serum interleukin-8 concentrations of H. pylori-infected patients appeared to modulate the gut microbiota of patients. However, none of the Lactobacillus strains had a significant effect on general blood physiological characteristics, serum tumor necrosis factor α concentrations, or serum pepsinogen concentrations in the patients.

CONCLUSION

Three Lactobacillus strains significantly alleviate the gastrointestinal discomfort and the gastric inflammatory response of H. pylori-infected patients. The activity of probiotics in eradicating H. pyloriinfection may be species/strain specific.

Dairy-Based Probiotic-Fermented Functional Foods: An Update on Their Health-Promoting Properties

Numerous studies have shown a link between the consumption of fermented dairy foods and improved health outcomes. Since the early 2000s, especially probiotic-based fermented functional foods, have had a revival in popularity, mostly as a consequence of claims made about their health benefits. Among them, fermented dairy foods have been associated with obesity prevention and in other conditions such as chronic diarrhea, hypersensitivity, irritable bowel syndrome, Helicobacter pylori infection, lactose intolerance, and gastroenteritis which all are intimately linked with an unhealthy way of life. A malfunctioning inflammatory response may affect the intestinal epithelial barrier’s ability to function by interfering with the normal metabolic processes. In this regard, several studies have shown that fermented dairy probiotics products improve human health by stimulating the growth of good bacteria in the gut at the same time increasing the production of metabolic byproducts. The fermented functional food matrix around probiotic bacteria plays an important role in the survival of these strains by buffering and protecting them from intestinal conditions such as low pH, bile acids, and other harsh conditions. On average, cultured dairy products included higher concentrations of lactic acid bacteria, with some products having as much as 109/mL or g. The focus of this review is on fermented dairy foods and associated probiotic products and their mechanisms of action, including their impact on microbiota and regulation of the immune system. First, we discussed whey and whey-based fermented products, as well as the organisms associated with them. Followed by the role of probiotics, fermented-product-mediated modulation of dendritic cells, natural killer cells, neutrophils, cytokines, immunoglobulins, and reinforcement of gut barrier functions through tight junction. In turn, providing the ample evidence that supports their benefits for gastrointestinal health and related disorders.

Complete Genome Sequence of Lactobacillus salivarius AR809, a Probiotic Strain with Oropharyngeal Tract Resistance and Adhesion to the Oral Epithelial Cells

Lactobacillus salivarius AR809 was isolated from a healthy adult oral cavity with multiple probiotic properties, such as high antimicrobial activity, adhesion to the oral epithelium, resistance to acidic pH, bile, lysozyme, and H₂O₂. In this study, to investigate the genetic basis on probiotic potential and identify the functional genes in the strain, the complete genome of strain AR809 was sequenced by Illumina and PacBio platforms. Then comparative genome analysis on 11 strains of Lactobacillus salivarius was performed. The complete genome of AR809 consisted of a circular 1,747,224 bp chromosome with 33.00% GC content and four circular plasmids [pA (247,948 bp), pB (27,292 bp), pC (3349 bp), and pD (2898 bp), respectively]. From among the 1866 protein-coding genes, 130 carbohydrate metabolism-related genes, 18 bacteriocin biosynthesis-related genes, 74 environmental stress-related genes, and a series of adhesion-related genes were identified via clusters of orthologous genes, Koyto Encyclopedia of Genes and Genomes, and carbohydrate-active enzymes annotation. The comparative genome analysis indicated that genomic homology between AR809 and CICC23174 was the highest. In conclusion, the present work provided valuable insights into the gene's function prediction and understanding the genetic basis on adapting to host oropharyngeal-gastrointestinal tract in strain AR809.

Modulation of the PI3K/Akt/mTOR signaling pathway by probiotics as a fruitful target for orchestrating the immune response

The mammalian target of rapamycin (mTOR) and the phosphatidylinositol-3-kinase (PI3K)/protein kinase B or Akt (PKB/Akt) signaling pathways are considered as two but somewhat interconnected significant immune pathways which play complex roles in a variety of physiological processes as well as pathological conditions. Aberrant activation of PI3K/Akt/mTOR signaling pathways has been reported to be associated in a wide variety of human diseases. Over the past few years, growing evidence in in vitro and in vivo models suggest that this sophisticated and subtle cascade mediates the orchestration of the immune response in health and disease through exposure to probiotics. An expanding body of literature has highlighted the contribution of probiotics and PI3K/Akt/mTOR signaling pathways in gastrointestinal disorders, metabolic syndrome, skin diseases, allergy, salmonella infection, and aging. However, longitudinal human studies are possibly required to verify more conclusively whether the investigational tools used to understand the regulation of these pathways might provide effective approaches in the prevention and treatment of various disorders. In this Review, we summarize the experimental evidence from recent peer-reviewed studies and provide a brief overview of the causal relationship between the effects of probiotics and their metabolites on the components of PI3K/Akt/mTOR signaling pathways and human disease.

Probiotics and gut microbiota: mechanistic insights into gut immune homeostasis through TLR pathway regulation

Consumption of probiotics as a useful functional food improves the host's wellbeing, and, when paired with prebiotics (indigestible dietary fibre/carbohydrate), often benefits the host through anaerobic fermentation.

The Beneficial Effects of Probiotics via Autophagy: A Systematic Review

Probiotics are living microorganisms increasingly used to treat or modulate different diseases or disorders because of their benefits and also low adverse reaction, and their positive and protective effects on various cells and tissues have been reported. The mechanisms by which probiotics exert their beneficial effects in different cells and tissues were investigated, and autophagy is one of the main mechanisms to induce their positive effects. Autophagy is a conserved process that occurs in all eukaryotic cells and plays an essential role in homeostasis and cell survival by degrading damaged and dysfunctional intracellular organelles. On the other hand, the role of autophagy is diverse in different tissues and situations, and cell death derived from autophagy has been observed in some cells. This search was done in PubMed, WOS, and Scopus using the keywords probiotic, microbiota, and autophagy. The search strategy was focused on the in vitro and animal model studies, and the included filters were English language publications and full-text articles (by June 2020). Studies that investigated other underlying mechanisms except autophagy were excluded. Among more than 105 papers, 24 studies were considered eligible for more evaluation. The obtained results indicated that most studies were performed on intestinal cell lines or tissue compared with other types of cell lines and tissue. This review article discusses our current understanding of the probiotic effects through autophagy in different cell lines and tissues that would be a useful guide to daily and clinical usage of these living microorganisms, but despite promising results of this systematic review, further studies need to assess this issue. This systematic review has demonstrated that autophagy is an effective mechanism in inducing beneficial effects of probiotics in different tissues.

Ligilactobacillus salivarius functionalities, applications, and manufacturing challenges

Ligilactobacillus salivarius is a lactic acid bacteria that has been gaining attention as a promising probiotic. Numerous strains exhibit functional properties with health benefits such as antimicrobial activity, immunological effects, and the ability to modulate the intestinal microbiota. However, just a small number of them are manufactured at an industrial scale and included in commercial products. The under exploitation of L. salivarius strains that remain in the freezer of companies is due to their incapacity to overcome the environmental stresses induced by production and stabilization processes.The present study summarizes the functionalities and applications of L. salivarius reported to date. It aims also at providing a critical evaluation of the literature available on the manufacturing steps of L. salivarius concentrates, the bacterial quality after each step of the process, and the putative degradation and preservation mechanisms. Here, we highlight the principal issues and future research challenges for improving the production and long-term preservation at the industrial scale of this microorganism, and probably of other probiotics.Key points• L. salivarius beneficial properties and commercialized products.• Production conditions and viability of L. salivarius after stabilization processes.• Prospects for identifying preservation mechanisms to improve L. salivarius stability.

The potential of Quercetin to protect against loperamide-induced constipation in rats

Constipation is the most common gastrointestinal complaint all over the world, and it is a risk factor of colorectal cancer. In this study, the protective of Quercetin against loperamide-induced constipation and its potential mechanism in a rat model were investigated. Results showed that Quercetin at 25 mg/kg and 50 mg/kg could significantly (p < .05) increase the intestinal transit rate, motilin, gastrin, substance P levels, and concentration of short-chain fatty acids (SCFAs), reduce the somatostatin levels, and improve the gastrointestinal peristalsis of rats. In addition, the expression levels of enteric nerve-related factors, glial cell line-derived neurotrophic factor (GDNF), transient receptor potential vanilloid 1 (TRPV1), nitric oxide synthase (NOS), c-Kit, stem cell factor (SCF), and aquaporin 3 (AQP3) were examined by RT-qPCR and/or Western blot analysis. The results suggest that Quercetin relieves loperamide-induced constipation by increasing the levels of interstitial cells of Cajal markers (c-Kit and SCF), as well as AQP3. In conclusion, the present study suggested that Quercetin exerted a protective effect against loperamide-induced constipation, which may be associated with its role in regulation of multiple signal pathways.

Fisetin inhibits inflammation and induces autophagy by mediating PI3K/AKT/mTOR signaling in LPS-induced RAW264.7 cells

Background

Fisetin, a natural potent flavonoid, has various beneficial, pharmacological activities. In this study, we investigated expression changes of the fisetin regulating genes in lipopolysaccharide (LPS)-treated RAW264.7 cells and explored the role of fisetin in inflammation and autophagy.

Methods and results

Microarray analysis identified 1,071 genes that were regulated by fisetin in LPS-treated RAW264.7 cells, and these genes were mainly related to the process of immune system response. Quantitative real-time polymerase chain reaction and Bio-Plex analysis indicated that fisetin decreased the expression and secretion of several inflammatory cytokines in cells administered with LPS. Western blot analysis and immunofluorescence assay showed that fisetin decreased microtubule-associated protein 1 light-chain 3B (LC3B) and lysosome-associated membrane protein 1 (LAMP1) expression in LPS-treated cells, while the autophagy inhibitor chloroquine (CQ) could partially reverse this effect. In addition, fisetin reduced the elevated expression of p-PI3K, p-AKT and p-mTOR induced by LPS in a concentration-dependent manner.

Conclusions

Fisetin diminished the expression and secretion of inflammatory cytokines and facilitated autophagosome-lysosome fusion and degradation in LPS-treated RAW264.7 cells via inhibition of the PI3K/AKT/mTOR signaling pathway. Overall, the results of this study provide new clues for the anti-inflammatory mechanism of fisetin and explain the crosstalk between autophagy and inflammation to some extent.