COMPOSITIONS AND METHODS FOR DECREASING A POPULATION OF BILOPHILA WADSWORTHIA OR INHIBITING THE GROWTH THEREOF

Abstract

The present invention relates to the use of at least one Lactobacillus bacterium, or a composition comprising thereof or conditioned thereby, for decreasing a population of Bilophila wadsworthia or inhibiting the growth thereof

Claims

1. A method for decreasing a population of Bilophila wadsworthia or inhibiting the growth thereof comprising administering a composition comprising at least one Lactobacillus bacterium to an individual in need thereof.

2. The method of claim 1, wherein the bacterium is Lactobacillus rhamnosus.

3. The method of claim 1, wherein the bacterium is Lactobacillus rhamnosus CNCM I-3690.

4. The method of claim 1, comprising decreasing an intestinal population of Bilophila wadsworthia or inhibiting the growth thereof in the colon of the individual.

5. A method for reducing bile salts comprising administering a composition comprising at least one Lactobacillus bacterium to an individual in need thereof.

6. The method of claim 5, wherein said bile acids are serum or cecal bile acids.

7. The method of claim 5, wherein said bile acids are tauro-conjugated.

8. The method of claim 5, wherein the bacterium is Lactobacillus rhamnosus.

9. The method of claim 5, wherein the bacterium is Lactobacillus rhamnosus CNCM I-3690.

10. The method of claim 1, wherein the individual has a non-vegetarian diet and/or a high fat diet.

11. The method of claim 1, wherein the composition is a food product.

12. The method of claim 1, wherein the composition is a fermented dairy product.

Description

DESCRIPTION OF THE FIGURES

[0109] FIGS. 1 -12. B. wadsworthia synergizes with HFD to trigger stronger metabolic impairment.

[0110] FIG. 1: Fold change of B. wadsworthia relative from day 0 in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+) (n=16-28/group).

[0111] FIG. 2: B. wadsworthia load in small intestinal (SI), fecal and cecal content after 9 weeks of CD or HFD.

[0112] FIG. 3: Body weight gain (n=37-40/group) in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0113] FIG. 4: Blood glucose in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0114] FIG. 5: Insulin in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0115] FIG. 6: Homeostatic model assessment-insulin resistance (HOMA-IR) after 6 h of fasting in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0116] FIG. 7: Blood glucose level before and after oral glucose tolerance challenge (OGGT; 2 g/kg mouse; n=27-40/group) in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0117] FIG. 8: Area under the curve (AUC) of OGGT in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0118] FIG. 9: Lipid area, calculated as % area of interest (AOI), in liver cross-sections stained with H&E in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0119] FIG. 10: Representative pictures of liver stained with H&E in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0120] FIG. 11: Liver triglycerides after 6 h of food deprivation in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0121] FIG. 12: Spearman correlation of fasting glucose and B. wadsworthia load in the cecal content.

[0122] Statistical comparison was performed by first testing normality using Kolmogorov-Smirnov test and then ANOVA or Kruskal-Wallis test with Bonferroni or Dunn's post hoc test in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0123] FIGS. 13-17. B. wadsworthia augments HFD-induced bile acid dysmetabolism.

[0124] FIG. 13: Ratio of primary to secondary bile acids in cecum in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0125] FIG. 14: Stacked bar showing the bile acids concentration in the cecum in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0126] FIG. 15: Concentration of difference bile acids in the cecum. (*p<0.05 vs HFD-ASF, .sup.+p<0.05 vs HFD-ASF.sup.Bw+; n=5-6/group) in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0127] FIG. 16: Stacked bar showing the bile acids concentration in the serum in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0128] FIG. 17: Concentration of difference bile acids in the serum (*p<0.05, **p<0.05; n=5-6/group). Statistical comparison was performed by first testing normality using Kolmogorov-Smirnov test and then ANOVA or Kruskal-Wallis test with Bonferroni or Dunn's post hoc test in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0129] FIGS. 18-25 B. wadsworthia potentiates HFD-induced intestinal barrier dysfunction and inflammation.

[0130] FIG. 18: Soluble CD14 (sCD14) in the serum in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0131] FIG. 19: Concentration of FITC-dextran in the plasma 3 h post-gavage in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0132] FIG. 20: Concentration of lipocalin in the feces in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0133] FIG. 21: Cytokine production of mesenteric lymph node cells after 48 h stimulation with PMA-ionomycin in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0134] FIG. 22: Cytokines from ilealhomogenates in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0135] FIG. 23: Cytokines from jejunal homogenates in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0136] FIG. 24: Cytokines from liver homogenates in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

[0137] FIG. 25: Cytokine production of splenic cells after 48 h stimulation with PMA-ionomycin. Statistical comparison was performed by first testing normality using Kolmogorov-Smirnov test and then ANOVA or Kruskal-Wallis test with Bonferroni or Dunn's post hoc test (*p-value vs HFD, .sup.+p-value vs HFD.sup.Bw+; n=6-16/group) in mice fed with control diet (CD) or high-fat diet (HFD) and inoculated with B. wadsworthia (Bw+) and treated with L. rhamnosus CNCM I-3690 (Lr+).

EXAMPLES

[0138] Animal and Study Design

[0139] For conventional experiment, male C57BL/6J mice were purchased from Janvier (France) and used after 1 week of receipt. Mice at 5 weeks of age were fed ad libitum with purified control diet (CD, Envigo MD.120508) or high fat diet (HFD, 18% milk-fat, Envigo MD.97222) or for 9 weeks. For deliberate B. wadsworthia inoculation, after maintaining the mice in HFD or CD for 2 weeks, mice were inoculated via oral gavage with 10.sup.7 CFU of B. wadsworthia ATCC 49260 suspended in 200 l of medium (Bacteroides bile esculin with 1% Taurine and 0.5 mg/ml cysteine) or medium alone for 3 consecutive days. For L. rhamnosus CNCM I-3690 treatment, 1 week after the last B. wadsworthia inoculation, mice were gavaged daily with 10.sup.9 CFU of L. rhamnosus CNCM I-3690 suspended in 200 l of vehicle (phosphate buffer saline with 15% glycerol) or vehicle for 5 weeks. For cyclosporine experiment, 1 week after the last B. wadsworthia inoculation, mice were injected i.p. with ciclosporine (25 mg/kg; Sandimmum Novartis) or vehicle (PBS) 3 a week for 5 weeks.

[0140] For altered Schaedler flora (ASF) experiment, male C57BL/6J germ-free (GF) mice were obtained from Transgenese et Archivage Animaux Modeles (CNRS, UPS44, Orleans, France) and used after 1 week of receipt. Sterility was confirmed microscopically and by microbiological technique. ASF colonized mice were kindly provided by E. Verdu from McMaster University (Canada). Fresh cecal samples from ASF-colonized mice were suspended and diluted in pre-reduced sterile 0.9% NaCl with 15% glycerol (1 g in 10 ml) under anaerobic condition. Aliquots of ASF cecal suspension were stored at 80 C. GF mice (5 weeks of age) were inoculated via oral gavage with 200 l of ASF cecal suspension and maintained on either HFD or CD. 3 weeks after ASF inoculation, mice were orally gavaged with B. wadsworthia or medium for 3 consecutive days. 1 week after the last B. wadsworthia inoculation, mice were gavaged daily with 10.sup.9 CFU of L. rhamnosus CNCM I-3690 or vehicle for 4 weeks.

[0141] Weekly food consumption was measured cage-wise. Mice were fasted for 6 hours prior to sacrifice and then put to sleep using isoflurane. Mice were culled by cervical dislocation and appropriate tissues were harvested. All experiments were performed in accordance with the Comite dEthique en Experimentation Animale.

[0142] Oral Glucose Tolerance Test

[0143] Oral glucose tolerance test was performed 3-5 days before the sacrifice. Mice were fasted by removing the food and bedding 1 hour before the onset of light cycle. After 6 hours of fasting, glucose solution (2 g/kg) was administered by oral gavage. Blood glucose level at time 0 (fasting glucose, taken before glucose gavage) and at 15, 30, 60 and 120 minutes after glucose gavage was analyzed using OneTouch glucometer (Roche). Glucose level was plotted against time and areas under the glucose curve (AUC) were calculated by following trapezoidal rule. Plasma insulin concentration (collected in EDTA-coated tubes) at time 0 (fasting insulin) and 30 min was analyzed from tail vein blood (collected in EDTA-coated tubes) using ultra sensitive mouse insulin ELISA kit (Alpco). Homeostatic model assessment of insulin resistance (HOMA-IR) was calculated according to the formula: fasting glucose (nmol/L)fasting insulin (microU/L)/22.5.

[0144] Measurements of Plasma Parameters

[0145] Blood samples were collected in heparin-coated tubes via cardiac puncture, centrifuged and then plasma samples were stored at 80 C. Plasma cholesterol, triglycerides, high-density lipoprotein (HDL), aspartate transaminase (AST) and alanine transaminase (ALT) measurement were performed by the Plateforme de Biochimie (CRI, UMR 1149, Paris) using Olympus AU400 Chemistry Analyzer.

[0146] Measurements of Bile Acids

[0147] Measurement of bile acids (BA) composition and concentration in plasma and intestinal contents was performed by the Chemistry department at Saint Antoine Hospital (UMR 7203, France) using high performance liquid chromatography (HPLC, Agilent 1100, France) coupled in series with mass spectrometer (QTRAP 2000, Canada), as previously described.

[0148] Measurements of SCFA

[0149] Measurement of the short-chain fatty acids (SCFA) from fecal content was performed by the mass spectrometer platform at Universite de Nantes (IRS-UN, France) using gas chromatography coupled with mass spectrometry, as previously described.

[0150] Quantification of Cytokines

[0151] Single cell suspensions from mesenteric lymph node (MLN) and spleen were isolated by smashing the cells in 70 m mesh. 1106 cells were plated in 24 well-plate and then stimulated with phorbol 12-myristate 13-acetate (PMA, 50 ng/mL; Sigma-Aldrich) and ionomycin (1 uM; Sigma Aldrich) for 48 h at 37 C. Supernatants were collected and used for cytokine analysis.

[0152] 50 mg of intestinal tissues and liver samples were suspended in T-PER Tissue Protein Extraction Reagent (Thermo Scientific) and homogenized suing FastPrep (6 m/s in 40 s). Homogenates were centrifuged and supernatants were used for cytokine and total protein concentration analysis. Total protein concentration of the tissue homogenates were analyzed using Pierce BCA Protein Assay Kit (Thermo Scientific). Cytokine concentrations were normalized according to the measured protein concentration.

[0153] Cytokines were measured using Legendplex Mouse Inflammation Panel (Biolegend) or individual ELISA kit (R&D Mouse DuoSet IL-6; Mabtech IFN-, IL-17a ELISA kits; Ebioscience TNF- ELISA kit).

[0154] Liver Histology and Hepatic Triglycerides Measurement

[0155] A slice of left lobe of the liver was fixed in 4% PFA for 48 h and then transferred to ethanol, fixed in paraffin, trimmed, processed, sectioned into slices approximately 3 m thick, mounted on a glass slide and stained with hemataoxylin and eosin (H&E). Hepatic lipids were evaluated and quantified as previously described.

[0156] In-Vivo Intestinal Permeability and Plasma sCD14 Measurement

[0157] In-vivo assay of intestinal barrier function was performed using fluorescein-conjugated dextran (FITC-dextran, 3-5 kDA) method, as previously described (Martin et al, 2015). Briefly, on the day of sacrifice, FITC-dextran (0.6 mg/g of body weight) was administered to the mice by oral gavage and 3 h later, blood samples were collected in heparin-coated tubes. Fluorescence intensity was measured in the plasma using a microplate reader (Tecan). Plasma concentration of soluble CD14 (sCD14) was measured using CD14 ELISA kit (R&D).

[0158] Quantification of Fecal LCN2

[0159] Frozen fecal samples were weighed and reconstituted in cold PBS. Samples were then agitated on a FastPrep bead beater machine for 40 s at setting 6 using 4.5 mm glass beads to obtain homogenous fecal suspension. Samples were then centrifuged for 5 min at 10,000 g (4OC) and clear supernatants were collected and stored at 20 C. until analysis. LCN2 levels were estimated using Duoset murine LCN2 Elisa Kit (R&D) as per manufacturer's instructions and expressed as pg/mg of stool.

[0160] B. wadsworthia aggravates High Fat Diet-induced host metabolic impairment

[0161] To determine the consequence of B. wadsworthia abundance on host metabolic status, metabolic parameters were evaluated in mice after a period of high fat diet (HFD) feeding. HFDBw+ mice showed higher fasting glucose. Furthermore, significant increase in serum concentrations of aspartate transaminase (AST) and alanine transaminase (ALT) were observed in all HFD groups compared to chow diet (CD) fed mice, but there was no significant difference between HFD and HFDBw+ groups. Analysis of liver histology revealed that hepatic lipid content was significantly increased in HFDBw+ mice. In parallel, total hepatic triglyceride was significantly higher in HFDBw+ group than HFD, suggesting that B. wadsworthia have detrimental effects on this metabolic feature. All HFD-fed mice, regardless of treatment, had significantly elevated levels of total cholesterol and HDL in the plasma. Finally, a strong positive correlation between fasting glucose and B. wadsworthia load in the cecum was observed. Taken together, these results showed that the high abundance of B. wadsworthia potentiates specific HFD-induced host metabolic syndrome, with notable dysregulation of glucose homeostasis and liver function.

[0162] Preventing the over-abundance of B. wadsworthia in HFD reverts B. wadsworthia-associated metabolic dysfunctions

[0163] The inventors tested the ability of the L. rhamnosus CNCM I-3690 strain in the above-mentioned model. Daily oral gavage of L. rhamnosus CNCM I-3690 (Lr) induced a significant decrease in fecal B. wadsworthia load (FIG. 1). Similarly, L. rhamnosus CNCM I-3690 was able to further reduce B. wadsworthia expansion in cecum and small intestine (FIG. 2).

[0164] L. rhamnosus treated HFDBw+ mice (HFDBw+Lr+) showed reduced fasting glucose level, plasma insulin and HOMA-IR response (FIGS. 3-6). OGGT further revealed that HFDBw+Lr+ mice tended to control glucose level better than HFDBw+ (FIGS. 7-8). L. rhamnosus CNCM I-3690 also corrected the effect of HFD on insulin level (S4B)

[0165] B. wadsworthia further enhances High Fat Diet-induced bile acid dysmetabolism Host transcriptomic data revealed that B. wadsworthia modulates a number of genes involved in taurine metabolism, which is linked with bile acid homeostasis. Bile acids are increasingly recognized as important signaling factors and regulators of metabolism. As such, the inventors investigated the bile acid profile of mice harboring complex microbiota. The inventors found that HFD feeding leads to changes in bile acid composition in the cecum characterized by significantly higher total bile acids and elevated primary bile acids conjugates as opposed to secondary conjugates and decreased proportion of bile acids such as DCA and HDCA (FIGS. 13-15). B. wadsworthia tends to further dysregulate bile acid composition in the cecum with higher levels of taurocholic acid (TCA), a taurine-conjugated bile acid, as well as other bile acids such as UDCA and MCA-. Furthermore, in the serum of HFD-fed mice, taurine conjugated bile acid concentration was more than 100-fold higher compared to CD, with an even stronger increase in HFDBw+ group (FIGS. 16-17). In contrast, HFDBw+Lr+ showed lower total and taurine-conjugated bile acids compared to HFDBw+, suggesting the efficiency of L. rhamnosus CNCM I-3690 to reverse the effect of HFD and B. wadsworthia on bile acids.

[0166] B. wadsworthia induces intestinal barrier dysfunction and amplifies HFD-driven inflammation that can be reverted by L. rhamnosus CNCM I-3690.

[0167] Based on the inventors simplified microbiota studies, the presence of B. wadsworthia up-regulated the global synthesis of LPS by the intestinal microbial communities and was further associated with higher systemic LPS. Guided by these results, the inventors similarly assessed the LPS availability in the systemic compartment in a HFD conventional mice model. In accordance with the results obtained from ASF-colonized mice, serum sCD14 level was significantly higher in HFDBw+ than in HFD mice (FIG. 18). L. rhamnosus CNCM I-3690 ameliorated this phenotype.

[0168] Intestinal barrier dysfunction is an important feature in obesity and metabolic syndrome.

[0169] The inventors hypothesized that this parameter may underlie the increased systemic bioavailability of LPS. Thus, the inventors assessed intestinal permeability using a classical permeability marker FITC-dextran. HFDBw+ mice exhibited increased intestinal permeability as demonstrated by higher serum FITC-dextran levels following oral gavage (FIG. 19). This phenotype was reduced by L. rhamnosus CNCM I-3690. Overall, these results show that the increased B. wadsworthia abundance augments the impact of HFD-induced gut barrier alterations and L. rhamnosus CNCM I-3690 partially reverses this effect.

[0170] Disruption of the gut barrier may allow increased intestinal permeability to bacterial endotoxins, such as LPS, and in turn may increase mucosal inflammation and lead to systemic inflammation. Hence, the inventors next examined whether B. wadsworthia further exacerbates

[0171] HFD-induced inflammatory response in conventional mice. The inventors first characterized the state of mucosal inflammation by quantifying lipocalin levels in the feces on different time-points during the duration of experiment (FIG. 20). HFD feeding tended to show higher levels of lipocalin in the feces compared to CD but this was further and significantly increased in HFDBw+ mice, particularly at week 7 and 9. Cytokine levels in MLN, ileum and jejunum of HFDBw+ were similarly higher compared to either CD or HFD or both groups, underscoring a state of heightened mucosal immune response in HFDBw+ group (FIGS. 21-23). L. rhamnosus CNCM I-3690 treatment was able to dampen some of these responses, particularly for fecal lipocalin levels, TNF- and IFN- (FIGS. 20-23).

[0172] The inventors further assessed the state of systemic inflammation and observed a similar pattern with significantly increased production of several pro-inflammatory cytokines such as IFN-, TNF- and IL-6 in the spleen and liver of HFDBw+ mice (FIGS. 24-25). Similar to mucosal immune response, L. rhamnosus CNCM I-3690 administration globally corrected B. wadsworthia-induced systemic inflammation. Taken together, these results showed that B. wadsworthia synergizes with HFD in inducing higher states of systemic and mucosal inflammation, which can be at least partly reversed by L. rhamnosus CNCM I-3690.

[0173] Discussion

[0174] High-saturated fat diets (HFD) were consistently associated with increase abundance of B. wadsworthia, a bacterium implicated in increase colitis severity of il-10/ mice. However, the impact of B. wadsworthia on non-genetically susceptible host, and whether and how its expansion could promote an impaired metabolic function remains poorly understood. Here, the inventors utilized a hypothesis-driven approach, to dissect how B. wadsworthia is able to modulate host metabolic response to HFD. The inventors then tested the hypothesis in conventional HFD murine model. The results showed that, beside intestinal pro-inflammatory effects, B. wadsworthia promotes intestinal barrier defect, systemic inflammation, bile acid dysmetabolism and changes in microbiome functional profile, leading to the worsening of HFD-induced metabolic effects. Moreover, the inventors showed that L. rhamnosus CNCM I-3960 was able to reverse the majority of B. wadsworthia-driven host metabolic and inflammatory impairments.

[0175] B. wadsworthia had been previously shown to expand in the presence of taurine conjugated bile acids, especially taurocholic acid (TCA). Similarly, the inventors observed that B. wadsworthia grow in-vitro 1 log colony forming units more in the presence of taurine (1%). Thus, in conjunction with previous results, this suggests that taurine and its derivatives, particularly TCA, may not be necessary for B. wadsworthia's survival but it is essential for its increased fitness and growth.

[0176] Bile acids are synthesized from cholesterol. In the liver, taurine, along with glycine, are used to conjugate bile acids to produce primary bile acids. Bile acids undergo enterohepatic circulation, which includes circulating in the intestine where primary bile acids are deconjugated and converted into secondary bile acids by the microbiota. Saturated animal-derived fats had been previously shown to promote the production of tauro-conjugated bile acids, such as TCA. The inventors showed that HFD significantly up-regulates genes involved in taurine metabolism with increased concentration of taurine conjugated bile acids and decreased proportion of secondary bile acids. B. wadsworthia further deregulates the bile acid disproportion in HFD context and this can be reversed by L. rhamnosus CNCM I-3690 treatment. Secondary bile acids have an important negative feedback role in decreasing bile acid synthesis; hence, the increased total serum and cecum bile acids in HFDBw+ group may be compounded by the decreased proportion of secondary bile acids. Additionally, unlike conjugated bile acids, unconjugated bile acids, such as cholic acid and chenodeoxycholic acid, are strong agonist for bile acid receptors such as Farnesoid X receptor and transmembrane G protein-coupled receptor. Signaling through these receptors activates transcriptional networks and signaling cascades relevant for cholesterol and lipid metabolism, maintenance of glucose and hepatic homeostasis, as well as genes involved in suppressing inflammation and strengthening intestinal barrier function. Similarly, previous studies have shown the pro-inflammatory properties of primary bile acids. Taken together, this suggest that B. wadsworthia's impact on bile acid metabolism may underlie the mechanism by which the bacterium potentiates HFD-induced metabolic impairment and host dysfunctions, particularly inflammation and barrier dysfunction.

[0177] To further determine the mechanistic basis by which B. wadsworthia impacts host metabolism and how L. rhamnosus CNCM I-3690 modulate these effects, the inventors performed transcriptomic analysis on both the host and microbiota. To fully understand the system, the inventors chose to work in a controlled microbiota environment, wherein bacterial and host function can be inferred to a specific microbe or condition. One of the key findings from said metatranscriptomics studies revealed that LPS synthesis pathway is highly up-regulated in HFDBw+ mice microbiota. This was paralleled by higher LPS translocation, which may at least partly explain the increased systemic inflammatory response the inventors observed in HFDBw+, both in ASF-colonized and conventional mice. L. rhamnosus CNCM I-3690 may be modulating the pro-inflammatory phenotype in HFDBw+ mice by decreasing the abundance of B. wadsworthia and/or through its intrinsic anti-inflammatory effects.

[0178] In addition to LPS synthesis, the presence of B. wadsworthia induced a decreased expression of microbial genes involved in butanoate metabolism in ASF-colonized mice. Furthermore, the decreased production of butyrate was confirmed by dosage in colon lumen. Aside from its effect in modulating inflammatory response, butyrate had been shown to reverse the increased intestinal permeability by assembly of tight junctions. Furthermore, dietary supplementation with butyrate had been previously shown to have preventive and therapeutic benefits in animal model of obesity and insulin resistance.