Orally administered Lactiplantibacillus plantarum OLL2712 decreased intestinal permeability, especially in the ileum: Ingested lactic acid bacteria alleviated obesity-induced inflammation by collaborating with gut microbiota

Regulation of IL-10 production in dendritic cells is controlled by the co-activation of TLR2 and Mincle by Lactiplantibacillus plantarum OLL2712

We showed that Lactiplantibacillus plantarum OLL2712 (OLL2712) strongly induces interleukin (IL)-10 production in immune cells. Although beneficial effects of this strain have been observed in both mice and humans, the mechanisms underlying IL-10 induction remain unclear. In this study, we found that OLL2712 co-activates two pattern recognition receptors, leading to IL-10 production in the mouse-derived thermosensitive dendritic cell line, tsDC. We first revealed the involvement of the Toll-like receptor (TLR)2-Myeloid differentiation primary response gene (MYD) 88 pathway in OLL2712-induced IL-10 production in tsDCs. However, stimulation with the TLR2 agonist alone was insufficient to induce IL-10 production. Consequently, we explored additional signaling pathways and found that the phosphorylation of spleen tyrosine kinase (Syk) was important in response to OLL2712, which was not triggered by a TLR2 agonist alone. Notably, the activation of Syk was found to depend on macrophage-inducible C-type lectin receptor (Mincle), one of the C-type lectin receptors. However, the surface-expressed Mincle is not responsible for the IL-10 production by OLL2712. Instead, it depends on the incorporation of OLL2712 into tsDCs, suggesting that Mincle recognizes incorporated OLL2712 intracellularly. In summary, OLL2712 is initially recognized by TLR2, which subsequently induces the expression of Mincle to recognize incorporated OLL2712, ultimately inducing IL-10 production.IMPORTANCEThe objective of this study is to elucidate the mechanism by which Lactiplantibacillus plantarum OLL2712 (OLL2712), previously identified by our research group as a potent stimulator of interleukin-10 production in immune cells, exerts its immunomodulatory effects. Our findings indicate that OLL2712 acts in synergy with two pattern-recognition receptors: Toll-like receptor 2 and Macrophage inducible C-type lectin receptor (Mincle). Additionally, we observed that OLL2712 needs to be internalized intracellularly to be recognized by Mincle. These findings represent the first insights into the detailed mechanism underlying the anti-inflammatory effects of OLL2712.

γ-Linolenic acid derived from Lactobacillus plantarum MM89 induces ferroptosis in colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide; however, current treatment options are inadequate, necessitating the exploration of new therapeutic strategies. The microbiota significantly influences the tumor microenvironment, suggesting that probiotics may serve as promising candidates for cancer treatment. We previously identified a novel probiotic, Lactobacillus plantarum MM89 (L. plantarum MM89), which was found to regulate the immune microenvironment. However, its specific role in CRC remained unclear. In this study, we employed an azoxymethane/dextran sodium sulfate-induced carcinogenesis mouse model to evaluate the therapeutic effects of L. plantarum MM89 in vivo. Transcriptome analysis was conducted to elucidate the mechanisms of action of L. plantarum MM89. Ferroptosis induction in tumor cells was assessed through cell viability assays and C11-BODIPY staining. Liquid chromatography/mass spectrometry was used to identify metabolites derived from L. plantarum MM89. MitoTracker and MitoTracker CMXRos staining and ATP content measurements were performed to assess mitochondrial damage. L. plantarum MM89 significantly inhibited tumor growth in vivo and alleviated intestinal inflammation at non-tumor foci. Transcriptome analysis and immunohistochemistry revealed that L. plantarum MM89 enhanced arachidonic acid metabolism. Small molecules present in the L. plantarum MM89 supernatant induced ferroptosis in cancer cells, as indicated by cell viability and C11-BODIPY assays. Furthermore, γ-linolenic acid (γ-LA) derived from L. plantarum MM89 was shown to induce ferroptosis via mitochondrial damage. In conclusion, γ-LA derived from L. plantarum MM89 triggers ferroptosis in tumor cells by inducing mitochondrial damage, highlighting its potential as a novel therapeutic agent for CRC treatment.

Postbiotics from Saccharomyces cerevisiae RC016 Cell Wall (Formerly Classified as a Prebiotic): Exploring In Vitro and In Vivo Benefits

The objective of this work was to obtain postbiotics derived from the cell wall of Saccharomyces cerevisiae RC016 by applying different strategies and to characterize them in terms of their antitoxin capacity in vitro and their in vivo impact on intestinal integrity, evaluating the modulation of the microbiota and the histomorphometry of the intestine. Moreover, the impact of dried strategies on chemical groups related to food toxin adsorption was analyzed. Nine mechanical and enzymatic cell disruption treatments were assayed using S. cerevisiae RC016 biomass to obtain the postbiotic under study. Then, postbiotics were characterized using high-resolution optical microscopy and assayed for in vitro studies related to their antitoxin activity (adsorption and degradation of aflatoxin B1). Postbiotics were dried using freeze-dried and spray-dried methods and subjected to FT-IR spectroscopy. Finally, the postbiotic efficacy was determined on an in vivo study conducted on 16 male and female BALB/c mice, divided into two experimental groups, each experimental group (n = 8) separated by sex in different cages (four females and four males): untreated (control) and yeast wall treated (YW); (a) female control; (b) male control; (c) female control + YW; (d) male control + YW. The intestinal microbiota showed significant differences in the counts of LAB and enterobacteria between male and female animals. The histomorphometric analysis showed a significant increase in villi height and width, as well as crypt depth, compared to the control group in male mice with the addition of the postbiotic solution of S. cerevisiae. These findings open new avenues for further optimizing postbiotics' production processes and evaluating their efficacy across diverse conditions and populations.

Intestinal barrier permeability: the influence of gut microbiota, nutrition, and exercise

The intestinal wall is a selectively permeable barrier between the content of the intestinal lumen and the internal environment of the body. Disturbances of intestinal wall permeability can potentially lead to unwanted activation of the enteric immune system due to excessive contact with gut microbiota and its components, and the development of endotoxemia, when the level of bacterial lipopolysaccharides increases in the blood, causing chronic low-intensity inflammation. In this review, the following aspects are covered: the structure of the intestinal wall barrier; the influence of the gut microbiota on the permeability of the intestinal wall via the regulation of functioning of tight junction proteins, synthesis/degradation of mucus and antioxidant effects; the molecular mechanisms of activation of the pro-inflammatory response caused by bacterial invasion through the TLR4-induced TIRAP/MyD88 and TRAM/TRIF signaling cascades; the influence of nutrition on intestinal permeability, and the influence of exercise with an emphasis on exercise-induced heat stress and hypoxia. Overall, this review provides some insight into how to prevent excessive intestinal barrier permeability and the associated inflammatory processes involved in many if not most pathologies. Some diets and physical exercise are supposed to be non-pharmacological approaches to maintain the integrity of intestinal barrier function and provide its efficient operation. However, at an early age, the increased intestinal permeability has a hormetic effect and contributes to the development of the immune system.

Immunomodulatory Activity on Human Macrophages by Cell-Free Supernatants to Explore the Probiotic and Postbiotic Potential of Lactiplantibacillus plantarum Strains of Plant Origin

Upon dietary administration, probiotic microorganisms can reach as live cells the human gut, where they interact with the microbiota and host cells, thereby exerting a beneficial impact on host functions, mainly through immune-modulatory activities. Recently, attention has been drawn by postbiotics, i.e. non-viable probiotic microbes, including their metabolic products, which possess biological activities that benefit the host. Lactiplantibacillus plantarum is a bacterial species that comprises recognised probiotic strains. In this study, we investigated in vitro the probiotic (and postbiotic) potential of seven L. plantarum strains, including five newly isolated from plant-related niches. The strains were shown to possess some basic probiotic attributes, including tolerance to the gastrointestinal environment, adhesion to the intestinal epithelium and safety. Besides, their cell-free culture supernatants modulated cytokine patterns in human macrophages in vitro, promoting TNF-α gene transcription and secretion, while attenuating the transcriptional activation and secretion of both TNF-α and IL-8 in response to a pro-inflammatory signal, and enhancing the production of IL-10. Some strains induced a high IL-10/IL-12 ratio that may correlate to an anti-inflammatory capacity in vivo. Overall, the investigated strains are good probiotic candidates, whose postbiotic fraction exhibits immunomodulatory properties that need further in vivo studies. The main novelty of this work consists in the polyphasic characterisation of candidate beneficial L. plantarum strains obtained from relatively atypical plant-associated niches, by an approach that explores both probiotic and postbiotic potentials, in particular studying the effect of microbial culture-conditioned media on cytokine pattern, analysed at both transcriptional and secretion level in human macrophages.

Ingesting probiotic yogurt containing Lactiplantibacillus plantarum OLL2712 improves glycaemic control in adults with prediabetes in a randomized, double-blind, placebo-controlled trial

AIM

The ingestion of Lactiplantibacillus plantarum OLL2712 (OLL2712) cells has been shown to improve glucose metabolism by suppressing chronic inflammation in murine models and clinical studies. This study aimed to clarify the effect of OLL2712 on glycaemic control in healthy adults with prediabetes.

MATERIALS AND METHODS

The study was a randomized, double-blind, placebo-controlled, parallel-group design. Adult participants with prediabetes [n = 148, glycated haemoglobin (HbA1c) range: 5.6%-6.4%, age range: 20-64 years] were assigned randomly to placebo or OLL2712 groups (n = 74/group) and administered daily for 12 weeks either conventional yogurt or yogurt containing >5 × 109 heat-treated OLL2712 cells, respectively. In addition, the participants were followed for 8 weeks after the discontinuation of either yogurt. The primary outcome was the changes in HbA1c levels at weeks 12 and 16 by analysis of covariance.

RESULTS

The levels of HbA1c and glycoalbumin decreased significantly in both groups at week 12 in comparison with those at week 0, but only in the OLL2712 group at week 16. HbA1c levels decreased significantly at weeks 12 and 16 in the OLL2712 group in comparison with the placebo group (p = .014 and p = .006, respectively). No significant inter- and intragroup differences in HbA1c levels were observed at week 20.

CONCLUSIONS

The ingestion of OLL2712 prevents the deterioration of glycaemic control and maintains the HbA1c levels within the normal range in adults with prediabetes; yogurt probably exhibits similar effects, which may contribute to reducing the risk of developing type 2 diabetes.

The Preventive Mechanisms of Bioactive Food Compounds against Obesity-Induced Inflammation

Dietary patterns are promising strategies for preventing and treating obesity and its coexisting inflammatory processes. Bioactive food compounds have received considerable attention due to their actions against obesity-induced inflammation, with limited harmful side effects. They are perceived as food ingredients or dietary supplements other than those necessary to meet basic human nutritional needs and are responsible for positive changes in the state of health. These include polyphenols, unsaturated fatty acids, and probiotics. Although the exact mechanisms of bioactive food compounds' action are still poorly understood, studies have indicated that they involve the modulation of the secretion of proinflammatory cytokines, adipokines, and hormones; regulate gene expression in adipose tissue; and modify the signaling pathways responsible for the inflammatory response. Targeting the consumption and/or supplementation of foods with anti-inflammatory potential may represent a new approach to obesity-induced inflammation treatment. Nevertheless, more studies are needed to evaluate strategies for bioactive food compound intake, especially times and doses. Moreover, worldwide education about the advantages of bioactive food compound consumption is warranted to limit the consequences of unhealthy dietary patterns. This work presents a review and synthesis of recent data on the preventive mechanisms of bioactive food compounds in the context of obesity-induced inflammation.

Lactiplantibacillus plantarum OLL2712 Induces Autophagy via MYD88 and Strengthens Tight Junction Integrity to Promote the Barrier Function in Intestinal Epithelial Cells

Autophagy is an important system conserved in eukaryotes that maintains homeostasis by degrading abnormal proteins. Autophagy incompetence in intestinal epithelial cells causes the abnormal function of intestinal stem cells and other cells and damages intestinal barrier function. The disruption of the intestinal barrier causes chronic inflammation throughout the body, followed by impaired glucose and lipid metabolism. Lactiplantibacillus plantarum OLL2712 (OLL2712) is a lactic acid bacterium that induces interleukin-10 production from immune cells, alleviates chronic inflammation, and improves glucose and lipid metabolism. In this study, we hypothesized that OLL2712 exerts anti-inflammatory effects by inducing autophagy and ameliorating intestinal barrier dysfunction, and we investigated its autophagy-inducing activities and functions. Caco-2 cells stimulated with OLL2712 for 24 h showed an increased number of autolysosomes per cell, compared with unstimulated cells. Therefore, the permeability of fluorescein isothiocyanate dextran 4000 (FD-4) was suppressed by inducing autophagy. In contrast, mucin secretion in HT-29-MTX-E12 cells was also increased by OLL2712 but not via autophagy induction. Finally, the signaling pathway involved in autophagy induction by OLL2712 was found to be mediated by myeloid differentiation factor 88 (MYD88). In conclusion, our findings suggest that OLL2712 induces autophagy in intestinal epithelial cells via MYD88, and that mucosal barrier function is strengthened by inducing autophagy.