Lactobacillus curvatus WiKim38 isolated from kimchi induces IL-10 production in dendritic cells and alleviates DSS-induced colitis in mice

Gut microbiota modulation and effects of a diet enriched in apple pomace on inflammation in a DSS-induced colitis mouse model

Certain types of soluble dietary fibre, such as pectin and pectic oligosaccharides from different sources, have demonstrated protective effects against inflammation in DSS-induced colitis mouse models. In this work, we have evaluated the impact of a diet enriched in apple pomace (AP-diet), an agricultural by-product with a significant content of pectin and that previously demonstrated prebiotic properties in human fecal batch fermentation models, on the gut microbiota composition, intestinal damage and inflammation markers in a DSS-induced colitis model. We found that the apple pomace enriched diet (AP-diet), providing a significant amount of pectin with demonstrated prebiotic properties, was associated with a slower increase in the disease activity index, translating into better clinical symptomatology of the animals. Histological damage scoring confirmed less severe damage in those animals receiving an AP-diet before and during the DSS administration period. Some serum inflammatory markers, such as TNFα, also demonstrated lower levels in the group receiving the AP-diet, compared to the control diet. AP-diet administration is also associated with the modulation of key taxa in the colonic microbiota of animals, such as some Lachnospiraceae genera and Ruminococcus species, including commensal short chain fatty acid producers that could play a role in attenuating inflammation at the intestinal level.

Long-term administration of probiotics prevents gastrointestinal mucosal barrier dysfunction in septic mice partly by upregulating the 5-HT degradation pathway

Sepsis can impair gastrointestinal (GI) barrier integrity. Oral probiotics (PT) can maintain the balance of GI microflora and improve GI function. 5-Hydroxytryptamine (5-HT) is a key promoter of GI injury caused by sepsis. However, the mechanism by which PT attenuates sepsis by regulating 5-HT is not fully understood. In this study, C57BL6 mice were intragastric administrated with normal saline (NC) or PT once a day for 4 weeks before cecal ligation and puncture (CLP). Compared with NC-CLP mice, PT-CLP mice had lower clinical score, higher body temperature. The survival rate of PT-CLP mice was significantly improved. The levels of inflammatory cytokines and 5-HT were obviously decreased in PT-CLP mice, and GI peristalsis and barrier function were enhanced. Moreover, sepsis downregulated the expression of tight junction proteins, while PT pretreatment could maintain them at the level of sham operation group. Furthermore, PT pretreatment increased the expression of serotonin transporter and monoamine oxidase A. PT administration could inhibit NF-κB activity, and activate ERK activity. In conclusion, long-term supplementation of PT before CLP can prevent sepsis-induced GI mucosal barrier dysfunction in mice, which may be partially mediated by upregulating the 5-HT degradation pathway via activating ERK signaling.

Latilactobacillus curvatus FFZZH5L isolated from pickled cowpea enhanced antioxidant activity in Caenorhabditis elegans by upregulating the level of glutathione S-transferase

Latilactobacillus curvatus is a potential probiotic that possesses beneficial health properties and fermentation traits; however, the extent of understanding of the antioxidant activities of L. curvatus is limited. This study investigates the antioxidant activities of a new L. curvatus FFZZH5L strain. The strain exhibits broad tolerance to acids, bases and salts and demonstrated good adaption to the gastrointestinal environment, with a survival rate of 45% after 24 h of treatment in artificial gastrointestinal juice. Moreover, L. curvatus FFZZH5L exhibits inhibitory effects on Staphylococcus aureus, with a self-aggregation rate of 34.8% and a co-aggregation rate of 82.2%. In vitro, the DPPH radical scavenging ability and GSH-px enzyme activity of L. curvatus FFZZH5L reach 64.27% and 15.95 U mL-1, respectively. Treatment of C. elegans with L. curvatus FFZZH5L in vivo significantly extended the organism's lifespan. Furthermore, the activity of SOD, GSH-px and T-AOC was increased by 33.6%, 43.4% and 58.3%, respectively. Feeding C. elegans with L. curvatus FFZZH5L decreased the MDA, lipofuscin and ROS levels by 9%-36.4%. L. curvatus FFZZH5L effectively protected C. elegans against juglone-induced oxidative stress damage and led to a significant increase in the organism's survival under heat stress. The RT-qPCR analysis suggests that feeding C. elegans with L. curvatus FFZZH5L upregulates the expression levels of antioxidant-related genes including glutathione S-transferase 4 (gst-4), gst-1, gst-10, sod-3, sod-5, and sod-10 in C. elegans. Our investigation confirms the probiotic and antioxidant properties of L. curvatus, indicating its potential application in functional foods and the pharmaceutical industry.

Distribution, inducibility, and characteristics of Latilactobacillus curvatus temperate phages

Aim: Temperate phages are known to heavily impact the growth of their host, be it in a positive way, e.g., when beneficial genes are provided by the phage, or negatively when lysis occurs after prophage induction. This study provides an in-depth look into the distribution and variety of prophages in Latilactobacillus curvatus (L. curvatus). This species is found in a wide variety of ecological niches and is routinely used as a meat starter culture. Methods: Fourty five L. curvatus genomes were screened for prophages. The intact predicted prophages and their chromosomal integration loci were described. Six L. curvatus lysogens were analysed for phage-mediated lysis post induction via UV light and/or mitomycin C. Their lysates were analysed for phage particles via viral DNA sequencing and transmission electron microscopy. Results: Two hundred and six prophage sequences of any completeness were detected within L. curvatus genomes. The 50 as intact predicted prophages show high levels of genetic diversity on an intraspecies level with conserved regions mostly in the replication and head/tail gene clusters. Twelve chromosomal loci, mostly tRNA genes, were identified, where intact L. curvatus phages were integrated. The six analysed L. curvatus lysogens showed strain-dependent lysis in various degrees after induction, yet only four of their lysates appeared to contain fully assembled virions with the siphovirus morphotype. Conclusion: Our data demonstrate that L. curvatus is a (pro)phage-susceptible species, harbouring multiple intact prophages and remnant sequences thereof. This knowledge provides a basis to study phage-host interaction influencing microbial communities in food fermentations.

Anti-Inflammatory and Gut Microbiota Modulating Effects of Probiotic Lactobacillus paracasei MSMC39-1 on Dextran Sulfate Sodium-Induced Colitis in Rats

Probiotics have been shown to possess several properties, depending on the strain. Some probiotics have important roles in preventing infection and balancing the immune system due to the interaction between the intestinal mucosa and cells in the immune system. This study aimed to examine the properties of three probiotic strains using the tumor necrosis factor-alpha (TNF-α) inhibition test in colorectal adenocarcinoma cells (Caco-2 cells). It was revealed that the viable cells and heat-killed cells of the probiotic L. paracasei strain MSMC39-1 dramatically suppressed TNF-α secretion in Caco-2 cells. The strongest strains were then chosen to treat rats with colitis induced by dextran sulfate sodium (DSS). Viable cells of the probiotic L. paracasei strain MSMC39-1 reduced aspartate transaminase and alanine transaminase in the serum and significantly inhibited TNF-α secretion in the colon and liver tissues. Treatment with the probiotic L. paracasei strain MSMC39-1 alleviated the colon and liver histopathology in DSS-induced colitis rats. Furthermore, supplementation with probiotic L. paracasei strain MSMC39-1 increased the genus Lactobacillus and boosted the other beneficial bacteria in the gut. Thus, the probiotic L. paracasei strain MSMC39-1 exhibited an anti-inflammation effect in the colon and modulated the gut microbiota.

Does kimchi deserve the status of a probiotic food?

Kimchi is a traditional fermented vegetable side dish in Korea and has become a global health food. Kimchi undergoes spontaneous fermentation, mainly by lactic acid bacteria (LAB) originating from its raw ingredients. Numerous LAB, including the genera Leuconostoc, Weissella, and Lactobacillus, participate in kimchi fermentation, reaching approximately 9-10 log colony forming units per gram or milliliter of food. The several health benefits of LAB (e.g., antioxidant and anti-inflammatory properties) combined with their probiotic potential in complex diseases including obesity, cancer, atopic dermatitis, and immunomodulatory effect have generated an interest in the health effects of LAB present in kimchi. In order to estimate the potential of kimchi as a probiotic food, we comprehensively surveyed the health functionalities of kimchi and kimchi LAB, and their effects on human gut environment, highlighting the probiotics function.

Kimchi and Leuconostoc mesenteroides DRC 1506 Alleviate Dextran Sulfate Sodium (DSS)-Induced Colitis via Attenuating Inflammatory Responses

Ulcerative colitis (UC) is caused by inflammation only in the mucosa of the colon, and its incidence is increasing worldwide. The intake of probiotics is known to have a beneficial effect on the development of UC. In this study, we investigated the alleviating effects of kimchi (KC), a fermented food rich in probiotics, and Leuconostoc mesenteroides DRC 1506 (DRC) isolated from kimchi on UC. A freeze-dried kimchi suspension and DRC were orally given to mice at a dose of 1 × 10⁹ CFU/day for 3 weeks. Furthermore, 3% dextran sulfate sodium (DSS) in drinking water was given to induce UC. The KC and DRC groups reduced symptoms of colitis, such as disease activity index, decrease in colon length, colon weight-to-length ratio, and pathological damage to the colon caused by DSS treatment. The KC and DRC groups decreased the levels of pro-inflammatory cytokine (TNF-α) and increased anti-inflammatory cytokine (IL-10) in the colon tissues. At the mRNA and protein expression levels in the colon tissue, KC and DRC groups downregulated inflammatory factors and upregulated tight junction-related factors. Therefore, DRC, as well as KC supplementation, are potent in alleviating UC by improving the inflammatory response and mucosal barrier function in the colon.

Use of Vegetable Waste as a Culture Medium Ingredient Improves the Antimicrobial and Immunomodulatory Activities of Lactiplantibacillus plantarum WiKim0125 Isolated from Kimchi

Lactic acid bacteria (LAB) isolated from kimchi (a traditional Korean dish typically made of fermented cabbage) can provide various health benefits, including anti-obesity, antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. In this study, we examined the antimicrobial and immunomodulatory effects of Lactiplantibacillus plantarum WiKim0125 cultured in de Man, Rogosa, and Sharpe (MRS) medium containing vegetable waste. Live bacterial cells were eliminated via supernatant filtration or heat treatment. The cell-free supernatant (CFS) obtained from culture broth containing kimchi cabbage waste (KCW), cabbage waste (CW), or onion waste (OW) showed significantly higher antimicrobial activity against skin pathogens (Propionibacterium acnes and Staphylococcus aureus) and foodborne pathogens (Escherichia coli and Salmonella typhimurium), with inhibition zones ranging between 4.4 and 8.5 mm, compared to that in conventional MRS medium (4.0-7.3 mm). In lipopolysaccharide-stimulated RAW264.7 cells, both supernatant and heat-inactivated Lb. plantarum WiKim0125 from culture media containing KCW and CW suppressed the production of inflammatory cytokines (72.8% and 49.6%, respectively) and nitric oxide (62.2% and 66.7%, respectively) without affecting cell viability. These results indicate that vegetable waste can potentially increase the antimicrobial and immunoregulatory potency of LAB while presenting a molecular basis for applying postbiotics to health products.

Phenotype-genotype analysis of Latilactobacills curvatus from different niches: Carbohydrate metabolism, antibiotic resistance, bacteriocin, phage fragments and linkages with CRISPR-Cas systems

The potential probiotic function of Latilactobacills curvatus has attracted the attention of researchers. To explore the differences in the genomes of L. curvatus, nine strains were isolated from various sources, including feces and fermented vegetables and compared with 25 strains from the NCBI database. The findings indicated that the average genome size, GC content, and CDS of L. curvatus were 1.94 MB, 41.9%, and 1825, respectively. Its core genome is associated with transcription, translation, carbohydrate transport and metabolism, and defense functions. The pan-genome of L. curvatus was in a closed state. The genetic diversity of L. curatus is mainly manifested in its ability to use carbohydrates, antibiotic resistance, bacteriocin operon, and polymeric regularly interspaced short palindromic repeats (CRISPR)-Cas for bacterial immunity. The CRISPR system of 34 strains of L. curvatus was predominantly found to be of the IIA type with a few IIC and IE types. These findings will contribute to a better understanding of this species.

Protective Effect of Levilactobacillus brevis Against Yersinia enterocolitica Infection in Mouse Model via Regulating MAPK and NF-κB Pathway

Although the use of the probiotic bacterium Lactobacillus for the treatment and prevention of diseases caused by various pathogenic bacteria has received increasing attention in recent years, its mechanism remains incompletely understood. Levilactobacillus brevis 23017 is a select probiotic strain that can regulate the immunity of host animals and resist pathogen infections. In this study, we analyzed the effect of L. brevis 23017 on Yersinia enterocolitica intestinal infection in a BALB/c mouse model and discussed its underlying mechanism. We found that in the mouse model, L. brevis 23017 prevented the damage of villi in the small intestine and decelerated weight loss after Y. enterocolitica infection. Moreover, we focused on the mechanism of the protective effect of L. brevis 23017 from the perspective of the damage and repair of the intestinal mucosal barrier. We observed that L. brevis 23017 maintained a normal mucosal barrier by altering the expression of tight junction proteins. Notably, our results indicated that L. brevis 23017 effectively promoted the secretion of the intestine-specific secretory immunoglobulin A (SIgA) by B cells via regulating cytokines and oxidative damage levels. This mechanism may be the reason for its protective role in Y. enterocolitica infection. In addition, our results demonstrated that the mechanism of L. brevis 23017 was related to antibacterial colonization and inflammation regulation and closely related to antioxidative stress and SIgA promotion. The protective effect of L. brevis 23017 on mice was related to the signaling pathway protein p38 MAPK and the phosphorylation levels of NF-κB. Our study provided novel insight into the mechanism of Lactobacillus against pathogenic bacterial infections. Such insight is of great importance for the prevention, diagnosis, and treatment of related diseases.

Lactobacillus plantarum strains attenuated DSS-induced colitis in mice by modulating the gut microbiota and immune response

Gut microbiota has become a new therapeutic target in the treatment of inflammatory Bowel Disease (IBD). Probiotics are known for their beneficial effects and have shown good efficacy in the clinical treatment of IBD and animal models of colitis. However, how these probiotics contribute to the amelioration of IBD is largely unknown. In the current study, the DSS-induced mouse colitis model was treated with oral administration of Lactobacillus plantarum strains to investigate their effects on colitis. The results indicated that the L. plantarum strains improved dysbiosis and enhanced the abundance of beneficial bacteria related to short-chain fatty acids (SCFAs) production. Moreover, L. plantarum strains decreased the level of pro-inflammatory cytokines, i.e., IL-17A, IL-17F, IL-6, IL-22, and TNF-α and increased the level of anti-inflammatory cytokines, i.e., TGF-β, IL-10. Our result suggests that L. plantarum strains possess probiotic effects and can ameliorate DSS colitis in mice by modulating the resident gut microbiota and immune response.

Latilactobacillus curvatus BYB3 Isolated from Kimchi Alleviates Dextran Sulfate Sodium (DSS)-Induced Colitis in Mice by Inhibiting IL-6 and TNF-R1 Production

Recent studies have shown that probiotics have health-promoting effects, particularly intestinal immune modulation. In this study, we focused on the immunomodulatory properties of Latilactobacillus curvatus BYB3, formerly called Lactobacillus curvatus, isolated from kimchi. In a mouse model of 14-day dextran sulfate sodium (DSS)-induced colitis, treatment with L. curvatus BYB3 significantly decreased the disease activity index, colon length, and weight loss. Moreover, histological analyses showed that L. curvatus BYB3 protected the structural integrity of the intestinal epithelial layer and mucin-secreting goblet cells from DSS-induced damage, with only slight infiltration by immune cells. To evaluate the molecular mechanisms underlying L. curvatus BYB3-driven inhibition of interleukin 6 production, possible in vivo anti-inflammatory effects of L. curvatus BYB3 were examined in the same mouse model. In addition, significantly lower levels of IL-6 and tumor necrosis factor receptor 1 upregulation were seen in the DSS+BYB3 group (compared to that in the DSS group). These results indicate that L. curvatus BYB3 exhibits health-promoting effects via immune modulation; and therefore, it can be used to treat various inflammatory diseases.

FK506 and Lactobacillus acidophilus ameliorate acute graft-versus-host disease by modulating the T helper 17/regulatory T-cell balance

Background

Graft-versus-host disease (GvHD) is a critical complication after allogeneic hematopoietic stem cell transplantation (HSCT). The immunosuppressants given to patients undergoing allogeneic HSCT disturb the microbiome and the host immune system, potentially leading to dysbiosis and inflammation, and may affect immune function and bone marrow transplantation. The intestinal microbiome is a target for the development of novel therapies for GvHD. Lactobacillus species are widely used supplements to induce production of antimicrobial and anti-inflammatory factors.

Methods

We determined the effect of the combination of Lactobacillus acidophilus and FK506 on GvHD following major histocompatibility complex-mismatched bone marrow transplantation.

Results

The combination treatment suppressed IFN-γ and IL-17-producing T cell differentiation, but increased Foxp3⁺Treg differentiation and IL-10 production. Also, the combination treatment and combination treated-induced Treg cells modulated the proliferation of murine alloreactive T cells in vitro. Additionally, the combination treatment upregulated Treg-related genes—Nt5e, Foxp3, Ikzf2, Nrp1 and Itgb8—in murine CD4⁺-T cells. The combination treatment also alleviated GvHD clinically and histopathologically by controlling the effector T cell and Treg balance in vivo. Moreover, the combination treatment decreased Th17 differentiation significantly and significantly upregulated Foxp3 and IL-10 expression in peripheral blood mononuclear cells from healthy controls and liver transplantation (LT) patients.

Conclusions

Therefore, the combination of L. acidophilus and FK506 is effective and safe for patients undergoing allogeneic hematopoietic stem cell transplantation.

Immunomodulatory Activity of Extracellular Vesicles of Kimchi-Derived Lactic Acid Bacteria (Leuconostoc mesenteroides, Latilactobacillus curvatus, and Lactiplantibacillus plantarum)

Lactic acid bacteria present in Kimchi, such as Leuconostoc mesenteroides (Lm), Latilactobacillus curvatus (Lc), and Lactiplantibacillus plantarum (Lp) produce extracellular vesicles (ECVs) that modulate immune responses. The ECVs of probiotic Kimchi bacteria are abbreviated as LmV, LcV, and LpV. Treatment of macrophages (RAW264.7) with ECVs (LmV, LcV, and LpV) increased the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-6 (IL-6). Immunostimulatory effects exerted on the RAW264.7 cells were stronger after treatments with LmV and LcV than with LpV. Treatment of mice with LcV (1 mg/kg, orally) induced splenocyte proliferation and subsequent production of both NO and cytokines (INF-γ, TNF-α, IL-4, and IL-10). Furthermore, pre-treatment of macrophages and microglial cells with ECVs prior to LPS stimulation significantly attenuated the production of NO and pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6). Therefore, ECVs (LmV, LcV, and LpV) prevent inflammatory responses in the LPS-stimulated microglial cells by blocking the extracellular signal-regulated kinase (Erk) and p38 signaling pathways. These results showed that LmV, LcV, and LpV from Kimchi probiotic bacteria safely exert immunomodulatory effects.

Protective effect of Lactobacillus-containing probiotics on intestinal mucosa of rats experiencing traumatic hemorrhagic shock

This study was conducted to assess whether Lactobacillus-containing probiotics could protect intestinal mucosa in rats during traumatic hemorrhagic shock and to determine its underlying mechanisms. Healthy male Sprague–Dawley rats (300 ± 20 g) were randomly divided into four groups. During the study, reverse transcription polymerase chain reaction, western blotting, and hematoxylin and eosin methods were used. There was a significant increase in the expression of toll-like receptor 4 (TLR4) in the rats that experienced traumatic hemorrhagic shock, along with increased mRNA of tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6. Pretreatment with Lactobacillus-containing probiotics reduced TLR4 expression, decreased phosphorylation (Ser536) and acetylation (Lys310) of p65, and decreased TNF-α and IL-6 mRNA. The probiotics combined acetate Ringer’s group showed a less severe pathological manifestation compared to the other experimental groups. Lactobacillus-containing probiotics inhibited nuclear factor-kappa B signaling via the downregulation of TLR4, resulting in inflammatory homeostasis, which might be the mechanism whereby Lactobacillus protects the intestinal mucosa from damage caused by the traumatic hemorrhagic shock.

Probiotic-mediated p38 MAPK immune signaling prolongs the survival of Caenorhabditis elegans exposed to pathogenic bacteria

The host-microbiota cross-talk represents an important factor contributing to innate immune response and host resistance during infection. It has been shown that probiotic lactobacilli exhibit the ability to modulate innate immunity and enhance pathogen elimination. Here we showed that heat-inactivated probiotic strain Lactobacillus curvatus BGMK2-41 stimulates immune response and resistance of the Caenorhabditis elegans against Staphylococcus aureus and Pseudomonas aeruginosa. By employing qRT-PCR and western blot analysis we showed that heat-inactivated BGMK2-41 activated PMK-1/p38 MAPK immunity pathway which prolongs the survival of C. elegans exposed to pathogenic bacteria in nematode killing assays. The C. elegans pmk-1 mutant was used to demonstrate a mechanistic basis for the antimicrobial potential of BGMK2-41, showing that BGMK2-41 upregulated PMK-1/p38 MAPK dependent transcription of C-type lectins, lysozymes and tight junction protein CLC-1. Overall, this study suggests that PMK-1/p38 MAPK-dependent immune regulation by BGMK2-41 is essential for probiotic-mediated C. elegans protection against gram-positive and gram-negative bacteria and could be further explored for development of probiotics with the potential to increase resistance of the host towards pathogens.

Screening and Identification of Latilactobacillus curvatus Z12 From Rumen Fluid of an Adult Female Sika Deer as a Potential Probiotic for Feed Additives

Lactic acid bacteria (LAB) are the main microorganisms used as probiotics against gastrointestinal inflammation. The objective of this study was to evaluate the potential probiotic characteristics (antimicrobial activity, artificial gastrointestinal model resistance, cell surface hydrophobicity, and autoaggregation ability) and safety characteristics (hemolytic activity, antimicrobial resistance, and in vivo safety) of LAB isolated from the rumen fluid of an adult female sika deer. Two isolated strains identified as Latilactobacillus curvatus Z12 and Z19 showed good antimicrobial activity against enteropathogenic Escherichia coli (ATCC25922), Salmonella typhi (ATCC14028), and Staphylococcus aureus (ATCC25923). In addition, L. curvatus Z12 exhibited higher artificial gastrointestinal model resistance, cell surface hydrophobicity and autoaggregation ability than L. curvatus Z19. Therefore, regarding safety characteristics, only L. curvatus Z12 was evaluated. Upon assessment of safety, L. curvatus Z12 was negative for hemolytic activity and susceptible to penicillin G and cefamandole. Furthermore, an in vivo safety assessment showed that high-dose L. curvatus Z12 (109 CFU/mL) supplementation not only had no adverse effects on body weight gain, feed intake, and organ coefficients of treated mice but also played a key role in promoting the immune system maturation of treated mice. This research revealed that L. curvatus Z12 possesses desirable probiotic characteristics and could be used as a potential probiotic feed additive to improve sika deer health.

Cell-free culture supernatant of Lactobacillus curvatus Wikim38 inhibits RANKL-induced osteoclast differentiation and ameliorates bone loss in ovariectomized mice

This study was conducted to investigate the inhibitory effects of the cell-free culture supernatant of Lactobacillus curvatus Wikim 38 (LC38-CS) on RANKL-induced osteoclast differentiation and bone loss in a mice model of ovariectomy-induced post-menopausal osteoporosis. LC38-CS inhibited the RANKL-induced differentiation of bone marrow-derived macrophages (BMDMs) into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by LC38-CS treatment of RANKL-treated BMDMs. In addition, LC38-CS decreased the RANKL-induced activation of the TRAF6/NF-κB/MAPKs axis at the early stage and the expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. PRMT1 and ADMA levels, new biomarkers for osteoclastogenesis, were decreased by LC38-CS treatment. The administration of LC38-CS increased bone volume and bone mineral density in ovariectomized mice in μ-CT analysis. These findings suggest that LC38-CS inhibited RANKL-induced osteoclast differentiation by the downregulation of molecular mechanisms and exerted anti-osteoporotic effects.

Genotoxicity and subchronic general toxicity assessments of Lactobacillus curvatus WiKim 38 using Sprague-Dawley rats

Lactobacillus curvatus WiKim 38 (LCW), isolated from kimchi, has shown novel immunomodulatory and anti-inflammatory properties. In the present study, to obtain data on the safety of LCW, we performed three genotoxicity (bacterial reverse mutation, chromosome aberration, and micronucleus) and two general toxicity (single-dosing and 13-week repeated-dosing) studies. In the genotoxicity assessment, LCW showed no increased reverse mutation for 4 strains of Salmonella typhimurium and a strain of Escherichia coli. In addition, LCW did not induce chromosome aberrations at concentrations up to 5000 μg/mL in cultured Chinese hamster lung (CHL) cells and did not induce an increased frequency of micronuclei in the bone marrow cells of rats at concentrations up to 2000 mg/kg. In the acute toxicity study using Sprague-Dawley (SD) rats, the approximate lethal dose of LCW was determined to be over 5000 mg/kg body weight (b.w.) in both sexes. Finally, in the subchronic toxicity study, no LCW-related adverse effects were observed at concentrations up to 5000 mg/kg b.w./day. Consequently, LCW is considered not to have mutagenic effects, and its no-observed-adverse-effect-level (NOAEL) is 5000 mg/kg b.w., equivalent to approximately 4.71 × 109 CFU/kg b.w., suggesting the LCW could be a potential probiotic for humans based on its safety profile.

Harnessing the potential of Lactobacillus species for therapeutic delivery at the lumenal-mucosal interface

Lactobacillus species have been studied for over 30 years in their role as commensal organisms in the human gut. Recently there has been a surge of interest in their abilities to natively and recombinantly stimulate immune activities, and studies have identified strains and novel molecules that convey particular advantages for applications as both immune adjuvants and immunomodulators. In this review, we discuss the recent advances in Lactobacillus-related activity at the gut/microbiota interface, the efforts to probe the boundaries of the direct and indirect therapeutic potential of these bacteria, and highlight the continued interest in harnessing the native capacity for the production of biogenic compounds shown to influence nervous system activity. Taken together, these aspects underscore Lactobacillus species as versatile therapeutic delivery vehicles capable of effector production at the lumenal-mucosal interface, and further establish a foundation of efficacy upon which future engineered strains can expand.

Immunomodulation of dendritic cells by Lactobacillus reuteri surface components and metabolites

BACKGROUND

Lactic acid bacteria are commensal members of the gut microbiota and are postulated to promote host health. Secreted factors and cell surface components from Lactobacillus species have been shown to modulate the host immune system. However, the precise role of L. reuteri secreted factors and surface proteins in influencing dendritic cells (DCs) remains uncharacterized.

HYPOTHESIS

We hypothesize that L. reuteri secreted factors will promote DC maturation, skewing cells toward an anti-inflammatory phenotype. In acute colitis, we speculate that L. reuteri promotes IL-10 and dampens pro-inflammatory cytokine production, thereby improving colitis.

METHODS & RESULTS

Mouse bone marrow-derived DCs were differentiated into immature dendritic cells (iDCs) via IL-4 and GM-CSF stimulation. iDCs exposed to L. reuteri secreted factors or UV-irradiated bacteria exhibited greater expression of DC maturation markers CD83 and CD86 by flow cytometry. Additionally, L. reuteri stimulated DCs exhibited phenotypic maturation as denoted by cytokine production, including anti-inflammatory IL-10. Using mouse colonic organoids, we found that the microinjection of L. reuteri secreted metabolites and UV-irradiated bacteria was able to promote IL-10 production by DCs, indicating potential epithelial-immune cross-talk. In a TNBS-model of acute colitis, L. reuteri administration significantly improved histological scoring, colonic cytokine mRNA, serum cytokines, and bolstered IL-10 production.

CONCLUSIONS

Overall these data demonstrate that both L. reuteri secreted factors and its bacterial components are able to promote DC maturation. This work points to the specific role of L. reuteri in modulating intestinal DCs.

NEW & NOTEWORTHY

Lactobacillus reuteri colonizes the mammalian gastrointestinal tract and exerts beneficial effects on host health. However, the mechanisms behind these effects have not been fully explored. In this article, we identified that L. reuteri ATTC PTA 6475 metabolites and surface components promote dendritic cell maturation and IL-10 production. In acute colitis, we also demonstrate that L. reuteri can promote IL-10 and suppress inflammation. These findings may represent a crucial mechanism for maintaining intestinal immune homeostasis.

Latilactobacillus curvatus: A Candidate Probiotic with Excellent Fermentation Properties and Health Benefits

Latilactobacillus curvatus is a candidate probiotic that has been included in the list of recommended biological agents for certification by the European Food Safety Authority. According to the published genomic information, L. curvatus has several genes that encode metabolic pathways of carbohydrate utilization. In addition, there are some differences in cell surface complex related genes of L. curvatus from different sources. L. curvatus also has several genes that encode bacteriocin production, which can produce Curvacin A and Sakacin P. Due to its ability to produce bacteriocin, it is often used as a bioprotective agent in fermented meat products, to inhibit the growth of a variety of pathogenic and spoilage bacteria. L. curvatus exerts some probiotic effects, such as mediating the production of IL-10 by dendritic cells through NF-κB and extracellular regulated protein kinases (ERK) signals to relieve colitis in mice. This review is the first summary of the genomic and biological characteristics of L. curvatus. Our knowledge on its role in the food industry and human health is also discussed, with the aim of providing a theoretical basis for the development of applications of L. curvatus.

Weissella paramesenteroides WpK4 plays an immunobiotic role in gut-brain axis, reducing gut permeability, anxiety-like and depressive-like behaviors in murine models of colitis and chronic stress

The relationship between inflammatory bowel disease (IBD) and mood disorders is complex and involves overlapping metabolic pathways, which may determine comorbidity. Several studies have been shown that this comorbidity could worsen IBD clinical course. The treatment of ulcerative colitis is complex, and involves traditional therapy to promote the function of epithelial barrier, reducing exacerbated inflammatory responses. Recently, it has been shown that some probiotic strains could modulate gut-brain axis, reducing depressive and anxiety scores in humans, including IBD patients. Accordingly, this study aimed to evaluate the role of Weissella paramesenteroides WpK4 in murine models of ulcerative colitis and chronic stress. It was observed that bacterium ingestion improved health of colitis mice, reducing intestinal permeability, besides improving colon histopathological appearance. In stressed mice, bacterial consumption was associated with a reduced anxiety-like and depressive-like behaviors. In both assays, the beneficial role of W. paramesenteroides WpK4 was related to its immunomodulatory feature. It is possible to state that W. paramesenteroides WpK4 exerted their beneficial roles in gut-brain axis through their immunomodulatory effects with consequences in several metabolic pathways related to intestinal permeability and hippocampal physiology.

Unraveling microbial fermentation features in kimchi: from classical to meta-omics approaches

Kimchi is a traditional Korean fermented food prepared via spontaneous fermentation by various microorganisms originating from vegetables such as kimchi cabbage, radishes, and garlic. Recent advances in meta-omics approaches that integrate metataxonomics, metagenomics, metatranscriptomics, and metabolomics have contributed to explaining and understanding food fermentation processes. Kimchi microbial communities are composed of majorly lactic acid bacteria such as Leuconostoc, Lactobacillus, and Weissella and fewer eukaryotic microorganisms and kimchi fermentation are accomplished by complex microbial metabolisms to produce diverse metabolites such as lactate, acetate, CO₂, ethanol, mannitol, amino acids, formate, malate, diacetyl, acetoin, and 2, 3-butanediol, which determine taste, quality, health benefit, and safety of fermented kimchi products. Therefore, in the future, kimchi researches should be systematically performed using the meta-omics approaches to understand complex microbial metabolisms during kimchi fermentation. KEY POINTS: • Spontaneous fermentation by raw material microbes gives kimchi its unique flavor. • The kimchi microbiome is altered by environmental factors and raw materials. • Through the multi-omics approaches, it is possible to accurately analyze the diversity and metabolic characteristics of kimchi microbiome and discover potential functionalities.

Beneficial effect of immunobiotic strains on attenuation of Salmonella induced inflammatory response in human intestinal epithelial cells

Probiotic bacteria have the ability to modulate host immune responses and have potent therapeutic functional effects against several diseases, including inflammatory diseases. However, beneficial effects of probiotics are strain specific and their interactions with host immune cells to modulate inflammatory response are largely unknown. Intestinal epithelial cells (IECs), which are the first line of defense against invading pathogens, and connects between commensals/probiotics and immune system; therefore, in this study, we used human IECs to assess the probiotic effects of three selected Lactobacillus strains in vitro. An HT-29 colonic epithelial cell and HT-29/blood mononuclear cells co-culture system were stimulated with Lactobacillus followed by Salmonella for different hours, after which the mRNA level of cytokines, β-defensin-2 and negative regulators for TLR signaling and protein levels of ZO-1 and IκB-α were analyzed by real-time polymerase chain reaction and western blot analysis. L. brevis decreased Salmonella induced IL-6, IL-8, MCP-1 and IL-1β levels, whereas L. pentosus suppressed IL-6 and MCP-1 in HT-29 cells. Moreover, L. brevis was able to increase the mRNA levels of A20, Tollip, SIGIRR and IRAKM, while L. pentosus reduced the levels of A20, and IRAKM in response to Salmonella. In addition, decrease in protein level of TNF-α and increase in mRNA level of IL-10 was observed in L. brevis and L. pentosus treated HT-29 cells. Lactobacillus strains were differentially modulated ZO-1 and p-IκB-α in HT-29 cells treated with Salmonella. Overall, the results of this study indicate that Lactobacillus strains attenuate Salmonella induced inflammatory responses through beneficial modulation of TLR negative regulators and the NF-κB pathway.

Lactobacillus rhamnosus GG treatment improves intestinal permeability and modulates microbiota dysbiosis in an experimental model of sepsis

Decrease of 'health-benefiting' microbes and increase of pathogenic bacteria (a condition termed dysbiosis) in intensive care unit patients is considered to induce or aggravate sepsis (gut-origin sepsis). Orally administered probiotics have been effective in the prevention of nosocomial infections. However, the mechanisms of probiotic-induced anti-infection and anti-sepsis remain to be explored. In the present study, 4-week-old C57BL6 mice were orally administrated with Lactobacillus rhamnosus GG (LGG) or normal saline (control) 4 weeks prior to cecal ligation and puncture (CLP). A subset of the mice were sacrificed at 24 h post-CLP, and the others were used for survival studies. Ileum tissues, blood and fecal samples were collected. The survival rate of septic mice pretreated with LGG was significantly improved compared with untreated mice. The levels of inflammatory cytokines were reduced in LGG-pretreated septic mice. A decrease of colonic proliferation and epithelial tight junctions and an increase of colonic apoptosis were observed in control septic CLP+saline mice. LGG pretreatment reversed the colonic proliferation, apoptosis and expression of tight junction proteins to the levels of the sham group. LGG pretreatment improved the richness and diversity of intestinal microbiota in septic mice. The principal coordinates analysis clustering plots revealed a significant separate clustering in microbiota structure between three groups. Bacteria associated with energy consumption, including Bacteroidetes, with opportunistic infection, including Proteobacteria, Staphylococcaceae and Enterococcaceae, lipopolysaccharide producers, including Enterobacteriaceae, and facultative anaerobes, such as Bacteroidaceae and Erysipelotrichaceae, increased in septic mice. By contrast, bacteria associated with energy harvest, including Firmicutes, intestinal barrier function regulators, including Akkermansia, hepatic function regulators, including Coprococcus and Oscillospira, and obligate anaerobes, including Prevotellaceae, decreased in septic mice. With LGG pretreatment, the sepsis-induced microbiota dysbiosis was reversed. The present results elucidated the potential mechanism of LGG treatment in sepsis, by improving intestinal permeability and modulating microbiota dysbiosis.

Microbial Ecology of Fermented Vegetables and Non-Alcoholic Drinks and Current Knowledge on Their Impact on Human Health

Fermented foods are currently experiencing a re-discovery, largely driven by numerous health benefits claims. While fermented dairy, beer, and wine (and other alcoholic fermented beverages) have been the subject of intensive research, other plant-based fermented foods that are in some case widely consumed (kimchi/sauerkraut, pickles, kombucha) have received less scientific attention. In this chapter, the current knowledge on the microbiology and potential health benefits of such plant-based fermented foods are presented. Kimchi is the most studied, characterized by primarily acidic fermentation by lactic acid bacteria. Anti-obesity and anti-hypertension properties have been reported for kimchi and other pickled vegetables. Kombucha is the most popular non-alcoholic fermented drink. Kombucha's microbiology is remarkable as it involves all fermenters described in known fermented foods: lactic acid bacteria, acetic acid bacteria, fungi, and yeasts. While kombucha is often hyped as a "super-food," only antioxidant and antimicrobial properties toward foodborne pathogens are well established; and it is unknown if these properties incur beneficial impact, even in vitro or in animal models. The mode of action that has been studied and demonstrated the most is the probiotic one. However, it can be expected that fermentation metabolites may be prebiotic, or influence host health directly. To conclude, plant-based fermented foods and drinks are usually safe products; few negative reports can be found, but more research, especially human dietary intervention studies, are warranted to substantiate any health claim.

Lactobacillus brevis 23017 Relieves Mercury Toxicity in the Colon by Modulation of Oxidative Stress and Inflammation Through the Interplay of MAPK and NF-κB Signaling Cascades

Aims: Lactobacillus strains have protective effects against heavy metals while relieving oxidative stress and modulating the immune response. Mechanisms that ameliorate heavy metal toxicity and the relationship between probiotics and gut barrier protection in the process of heavy metal pathogenesis was poorly understood. Methods and Results: In this study, Lactobacillus brevis 23017 (LAB, L. brevis 23017), a selected probiotics strain with strong mercury binding capacities, was applied to evaluate the efficiency against mercury toxicity in a mouse model. Histopathological results along with HE stains show that L. brevis 23017 protects the integrity of the small intestinal villus, which slows weight loss in response to Hg exposure. The qRT-PCR results demonstrate that L. brevis 23017 maintains a normal mucosal barrier via modulation of tight junction proteins. Importantly, the present study demonstrates that L. brevis 23017 effectively ameliorates injury of the small intestine by reducing intestinal inflammation and alleviating oxidative stress in animal models. Moreover, L. brevis 23017 blocks oxidative stress and inflammation through MAPK and NF-κB pathways, as shown by western blot. Conclusions: Together, these results reveal that L. brevis 23017 may have applications in the prevention and treatment of oral Hg exposure with fermented functional foods by protecting gut health in daily life.

Acute infection with Strongyloides venezuelensis increases intestine production IL-10, reduces Th1/Th2/Th17 induction in colon and attenuates Dextran Sulfate Sodium-induced colitis in BALB/c mice

Helminth infection can reduce the severity of inflammatory bowel disease. However, the modulatory mechanisms elicited by helminth infection are not yet fully understood and vary depending on the experimental model. Herein we evaluated the effect of acute infection of BALB/c mice with Strongyloides venezuelensis on the clinical course of ulcerative colitis induced by Dextran Sulfate Sodium (DSS) treatment of these animals. For the experiments, S. venezuelensis-infected BALB/c mice were treated orally with 4% DSS solution for seven days. As controls, we used untreated S. venezuelensis infected, DSS-treated uninfected, and untreated/uninfected BALB/c mice. During DSS treatment, mice from the different groups were compared with regards to the clinical signs related to the severity of colitis and intestinal inflammation. Mice acutely infected with S. venezulensis and treated with DSS had reduced clinical score, shortening of the colon, and tissue inflammation. Moreover, DSS-treated and infected mice showed reduced IL-4, INF-γ, and IL-17 levels and increase of IL-10 production in the colon and/or in the supernatant of mesenteric lymph nodes cell cultures that resulted in lower eosinophil peroxidase and myeloperoxidase activity in colon homogenates, when compared with DSS-treated uninfected mice. DSS-treated infected mice also preserved the intestine architecture and had normal differentiation of goblet cells and mucus production in the colon mucosa. In conclusion, the data indicate that the clinical improvement reported in DSS-treated infected mice was accompanied by the lower production of Th1/Th2/Th17 pro-inflammatory cytokines, stimulation of IL-10, and induction of mucosal repair mechanisms.

Bacterial community analysis in three types of the fermented seafood, jeotgal, produced in South Korea

Jeotgal is a traditional Korean seafood fermented by indigenous microbes. The bacterial community in five myeolchi-jeot (Engraulis japonica), five meongge-jeot (Halocynthia roretzi), and six saeu-jeot (Acetes japonicas) produced in South Korea was analyzed by barcoded pyrosequencing targeting the V1/V2 hyper-variable regions of the 16S rRNA gene. All samples were dominated by the phyla Firmicutes, which represented 67.7% (SD = 27.2%) of the population. Tetragenococcus halophilus and Tetragenococcus muriaticus were the predominant species in myeolchi-jeot. The LABs, Lactobacillus sakei, Lactobacillus curvatus, and Weissella koreensis were the predominant species in meongge-jeot. In myeolchi-jeot and meongge-jeot, the bacterial communities within samples were consistent in their predominance, however each of saeu-jeot samples had inter-individual variety in the bacterial community leading to the difficulties of standardization for the commercial production of saeu-jeot. The results of this study will conclusively help to expand our basic knowledge of jeotgal and the related microorganisms involved in food fermentation.

Using murine colitis models to analyze probiotics-host interactions

Probiotics are defined as 'live microorganisms which when administered in adequate amounts confer a health benefit on the host'. So, to consider a microorganism as a probiotic, a demonstrable beneficial effect on the health host should be shown as well as an adequate defined safety status and the capacity to survive transit through the gastrointestinal tract and to storage conditions. In this review, we present an overview of the murine colitis models currently employed to test the beneficial effect of the probiotic strains as well as an overview of the probiotics already tested. Our aim is to highlight both the importance of the adequate selection of the animal model to test the potential probiotic strains and of the value of the knowledge generated by these in vivo tests.

Targeted Synthesis and Characterization of a Gene Cluster Encoding NAD(P)H-Dependent 3α-, 3β-, and 12α-Hydroxysteroid Dehydrogenases from Eggerthella CAG:298, a Gut Metagenomic Sequence

Gut metagenomic sequences provide a rich source of microbial genes, the majority of which are annotated by homology or unknown. Genes and gene pathways that encode enzymes catalyzing biotransformation of host bile acids are important to identify in gut metagenomic sequences due to the importance of bile acids in gut microbiome structure and host physiology. Hydroxysteroid dehydrogenases (HSDHs) are pyridine nucleotide-dependent enzymes with stereospecificity and regiospecificity for bile acid and steroid hydroxyl groups. HSDHs have been identified in several protein families, including medium-chain and short-chain dehydrogenase/reductase families as well as the aldo-keto reductase family. These protein families are large and contain diverse functionalities, making prediction of HSDH-encoding genes difficult and necessitating biochemical characterization. We located a gene cluster in Eggerthella sp. CAG:298 predicted to encode three HSDHs (CDD59473, CDD59474, and CDD59475) and synthesized the genes for heterologous expression in Escherichia coli We then screened bile acid substrates against the purified recombinant enzymes. CDD59475 is a novel 12α-HSDH, and we determined that CDD59474 (3α-HSDH) and CDD59473 (3β-HSDH) constitute novel enzymes in an iso-bile acid pathway. Phylogenetic analysis of these HSDHs with other gut bacterial HSDHs and closest homologues in the database revealed predictable clustering of HSDHs by function and identified several likely HSDH sequences from bacteria isolated or sequenced from diverse mammalian and avian gut samples.IMPORTANCE Bacterial HSDHs have the potential to significantly alter the physicochemical properties of bile acids, with implications for increased/decreased toxicity for gut bacteria and the host. The generation of oxo-bile acids is known to inhibit host enzymes involved in glucocorticoid metabolism and may alter signaling through nuclear receptors such as farnesoid X receptor and G-protein-coupled receptor TGR5. Biochemical or similar approaches are required to fill in many gaps in our ability to link a particular enzymatic function with a nucleic acid or amino acid sequence. In this regard, we have identified a novel 12α-HSDH and a novel set of genes encoding an iso-bile acid pathway (3α-HSDH and 3β-HSDH) involved in epimerization and detoxification of harmful secondary bile acids.

Potential of Lactobacillus plantarum ZDY2013 and Bifidobacterium bifidum WBIN03 in relieving colitis by gut microbiota, immune, and anti-oxidative stress

Ulcerative colitis (UC) is an inflammatory bowel disease that is difficult to cure, with rising incidence in recent decades. Probiotics have become a new strategy for UC treatment. In this study, we chose 2 new multisource probiotics, Lactobacillus plantarum ZDY2013 from acid beans and Bifidobacterium bifidum WBIN03 from infant feces, and a mixture of both, to investigate the anti-inflammatory and antioxidant effect on H₂O₂-induced oxidative damage in a HT-29 cell model and dextran sodium sulfate (DSS)-induced UC in mice. Compared with the model group, the general relative indices results showed L. plantarum ZDY2013 and B. bifidum WBIN03 have a significant effect on DSS-induced UC in mice, by downregulating the pro-inflammatory cytokines (e.g., TNF-α) and upregulating antioxidant factors (e.g., SOD1, SOD2, GPX2) at the transcriptional level. By means of high-throughput sequencing (16S V3-V4) and systematical bioinformatics analyses, we found that colitis may be associated with the changes in intestinal flora, especially Firmicutes and Bacteroides. Administration of L. plantarum ZDY2013 increased the abundance of Lactobacillus animalis, whereas B. bifidum WBIN03 increased the abundance of Lachnospiraceae bacterium COE1. Our results revealed that a supplement of L. plantarum ZDY2013 and B. bifidum WBIN03 remit UC through modification of gut microbiota to regulate oxidative stress and inflammatory mediators.

Draft Genome Sequence of Lactobacillus curvatus FLEC03, a Meat-Borne Isolate from Beef Carpaccio Packaged in a Modified Atmosphere

In this study, we present the draft genome sequence for Lactobacillus curvatus FLEC03. This strain was isolated from beef carpaccio packaged in a modified atmosphere. The draft genome will contribute to understanding the role of L. curvatus strains in food products (fermentation, biopreservation, or spoilage) through comparative genomics with other strains.

Complete Genome Sequence of Lactobacillus curvatus Strain WiKim38 Isolated from Kimchi

Lactobacillus curvatus WiKim38 is a potential probiotic strain isolated from kimchi, a traditional Korean fermented food. The complete genome of the WiKim38 strain consisted of a circular chromosome of 1,940,170 bp in length with a G+C content of 41.93%.

Effect of a probiotic beverage consumption (Enterococcus faecium CRL 183 and Bifidobacterium longum ATCC 15707) in rats with chemically induced colitis

Background

Some probiotic strains have the potential to assist in relieving the symptoms of inflammatory bowel disease. The impact of daily ingestion of a soy-based product fermented by Enterococcus faecium CRL 183 and Lactobacillus helveticus 416 with the addition of Bifidobacterium longum ATCC 15707 on chemically induced colitis has been investigated thereof within a period of 30 days.

Methods

Colitis was induced by dextran sulfate sodium. The animals were randomly assigned into five groups: Group C: negative control; Group CL: positive control; Group CLF: DSS with the fermented product; Group CLP: DSS with the non-fermented product (placebo); Group CLS: DSS with sulfasalazine. The following parameters were monitored: disease activity index, fecal microbial analyses, gastrointestinal survival of probiotic microorganisms and short-chain fatty acids concentration in the feces. At the end of the protocol the animals’ colons were removed so as to conduct a macroscopical and histopathological analysis, cytokines and nitrite quantification.

Results

Animals belonging to the CLF group showed fewer symptoms of colitis during the induction period and a lower degree of inflammation and ulceration in their colon compared to the CL, CLS and CLP groups (p<0.05). The colon of the animals in groups CL and CLS presented severe crypt damage, which was absent in CLF and CLP groups. A significant increase in the population of Lactobacillus spp. and Bifidobacterium spp. at the end of the protocol was verified only in the CLF animals (p<0.05). This group also showed an increase in short-chain fatty acids (propionate and acetate). Furthermore, the intestinal survival of E. faecium CRL 183 and B. longum ATCC 15707 in the CLF group has been confirmed by biochemical and molecular analyzes.

Conclusions

The obtained results suggest that a regular intake of the probiotic product, and placebo to a lesser extent, can reduce the severity of DSS-induced colitis on rats.

A lactic acid bacterium isolated from kimchi ameliorates intestinal inflammation in DSS-induced colitis

Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the present study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To investigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phosphate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cytokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2-administered mice compared with the controls. The administration of LS2 induced the increase of CD4⁺FOXP3⁺ Treg cells, which are responsible for IL-10. Numbers of macrophages (CD11b⁺ F4/80⁺), and neutrophils (CD11b⁺ Gr-1⁺) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.