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Faecalibacterium prausnitzii is a promising biomarker of a healthy human microbiota. However, previous studies reported the heterogeneity of this species and found the presence of several distinct groups at the species level among F. prausnitzii strains. Our recent study revealed that methods previously developed for quantification of F. prausnitzii were not specific to the species level because of the heterogeneity within the F. prausnitzii species and the application of 16S rRNA gene, which is an invalid genetic marker for the species. Therefore, previously available data failed to provide information on different groups, which limits our understanding of the importance of this organism for host health. Here, we propose an alternative gene marker for quantification of F. prausnitzii-related taxa. A total of nine group-specific primer pairs were designed by targeting rpoA gene sequences. The newly developed rpoA-based qPCR successfully quantified targeted groups. Application of the developed qPCR assay in six healthy adults revealed marked differences in abundance and prevalence among the different targeted groups in stool samples. The developed assay will facilitate detailed understanding of the impact of Faecalibacterium populations at the group level on human health and to understand the links between depletion of specific groups in Faecalibacterium and different human disorders.

Although arachidonic acid (ARA) is the precursor of the majority of eicosanoids, its influence as a food component on health is not well known. Therefore, we investigated its impact on the gut microbiota and gut–brain axis. Groups of male BALB/c mice were fed either a standard diet containing 5% lipids (Std-ARA) or 15%-lipid diets without ARA (HL-ARA) or with 1% ARA (HL + ARA) for 9 weeks. Fatty acid profiles of all three diets were the same. The HL-ARA diet favored the growth of Bifidobacterium pseudolongum contrary to the HL + ARA diet that favored the pro-inflammatory Escherichia–Shigella genus in fecal microbiota. Dietary ARA intake induced 4- and 15-fold colic overexpression of the pro-inflammatory markers IL-1β and CD40, respectively, without affecting those of TNFα and adiponectin. In the brain, dietary ARA intake led to moderate overexpression of GFAP in the hippocampus and cortex. Both the hyperlipidic diets reduced IL-6 and IL-12 in the brain. For the first time, it was shown that dietary ARA altered the gut microbiota, led to low-grade colic inflammation, and induced astrogliosis in the brain. Further work is necessary to determine the involved mechanisms.

Faecalibacterium prausnitzii is abundant in the healthy human intestinal microbiota, and the absence or scarcity of this bacterium has been linked with inflammatory diseases and metabolic disorders. F. prausnitzii thus shows promise as a next-generation probiotic for use in restoring the balance of the gut microbial flora and, due to its strong anti-inflammatory properties, for the treatment of certain pathological conditions. However, very little information is available about gene function and regulation in this species. Here, we utilized a systems biology approach - weighted gene co-expression network analysis (WGCNA) – to analyze gene expression in three publicly available RNAseq datasets from F. prausnitzii strain A2-165, all obtained in different laboratory conditions. The co-expression network was then subdivided into 24 co-expression gene modules. A subsequent enrichment analysis revealed that these modules are associated with different kinds of biological processes, such as arginine, histidine, cobalamin, or fatty acid metabolism as well as bacteriophage function, molecular chaperones, stress response, or SOS response. Some genes appeared to be associated with mechanisms of protection against oxidative stress and could be essential for F. prausnitzii’s adaptation and survival under anaerobic laboratory conditions. Hub and bottleneck genes were identified by analyses of intramodular connectivity and betweenness, respectively; this highlighted the high connectivity of genes located on mobile genetic elements, which could promote the genetic evolution of F. prausnitzii within its ecological niche. This study provides the first exploration of the complex regulatory networks in F. prausnitzii, and all of the “omics” data are available online for exploration through a graphical interface at https://feaprau.omics.ovh/.

Aging is characterized, at the systemic level, by the development of low-grade inflammation, which has been identified as determining sarcopenia by blunting postprandial muscle anabolism. The causes of this "inflammageing" is still not clearly defined. An increased intestinal permeability, a microbiota dysbiosis and subsequent generation of intestinal then generalized inflammation have been hypothesized. The objective of this study was to testYoung adult (6 m) and elderly rats (18 m) received Dextran Sodium Sulfate (DSS) for 28 days to generate low-grade intestinal inflammation, and received (PB1 or PB2 groups) or not (DSS group) one of the two S. Thermophilus strains (5 × 10In both adult and old rats, DSS reduced absolute protein synthesis (ASR) in gastrocnemius muscle [-12.4% (PB1) and -9.5% (PB2) vs. PF,The loss of muscle anabolism associated with low-grade intestinal inflammation can be prevented by supplementation with anti-inflammatory CNRZ160 strain. We propose that the moderated gut inflammation by CNRZ160 may result in curtailed amino acids (AA) utilization by the gut, and subsequent restored AA systemic availability to support muscle protein accretion. Therefore, CNRZ160 could be considered as an efficient probiotic to modulate muscle mass loss and limit sarcopenia during aging.

Faecalibacterium prausnitzii (F. prausnitzii), a dominant bacterium of the human microbiota, is decreased in patients with inflammatory bowel diseases (IBD) and exhibits anti-inflammatory effects. In human, colonic lamina propria contains IL-10-positive, Foxp3-negative regulatory T cells (Treg) characterized by a double expression of CD4 and CD8α (DP8α) and a specificity for F. prausnitzii. This Treg subset is decreased in IBD. The in vivo effect of DP8α cells has not been evaluated yet. Here, using a humanized model of NOD.Prkcscid IL2rγ-/- (NSG) immunodeficient mouse strain that expresses human leucocyte antigen D-related 4 (HLA-DR4) but not murine class II (NSG-Ab° DR4), we demonstrated a protective effect of DP8α Tregs combined with F. prausnitzii administration in a colitis model. In a cohort of patients with IBD, we showed an independent association between the frequency of circulating DP8α cells and disease activity. Finally, we pointed out a positive correlation between F. prausnitzii-specific DP8α Tregs and the amount of F. prausnitzii in fecal microbiota in healthy individuals and patients with ileal Crohn’s disease.

The commensal bacterium Faecalibacterium prausnitzii has unique anti-inflammatory properties, at least some of which have been attributed to its production of MAM, the Microbial Anti-inflammatory Molecule. Previous phylogenetic studies of F. prausnitzii strains have revealed the existence of various phylogroups. In this work, we address the question of whether MAMs from different phylogroups display distinct anti-inflammatory properties. We first performed wide-scale identification, classification, and phylogenetic analysis of MAM-like proteins encoded in different genomes of F. prausnitzii. When combined with a gene context analysis, this approach distinguished at least 10 distinct clusters of MAMs, providing evidence for functional diversity within this protein. We then selected 11 MAMs from various clusters and evaluated their anti-inflammatory capacities in vitro. A wide range of anti-inflammatory activity was detected. MAM from the M21/2 strain had the highest inhibitory effect (96% inhibition), while MAM from reference strain A2-165 demonstrated only 56% inhibition, and MAM from strain CNCM4541 was almost inactive. These results were confirmed in vivo in murine models of acute and chronic colitis. This study provides insights into the family of MAM proteins and generates clues regarding the choice of F. prausnitzii strains as probiotics for use in targeting chronic inflammatory diseases.

Abundance of Faecalibacterium prausnitzii, a dominant bacterium of the human microbiota that exhibits antiinflammatory effects, is decreased in patients with inflammatory bowel diseases (IBD). In humans, colonic lamina propria contains IL-10–secreting, Foxp3(–) Tregs characterized by a double expression of CD4 and CD8α (DP8α) and a specificity for F. prausnitzii. This Treg subset is decreased in IBD. The in vivo effect of DP8α cells has not been evaluated yet to our knowledge. Here, using a humanized model of a NSG immunodeficient mouse strain that expresses the HLA D–related allele HLA-DR*0401 but not murine class II (NSG-Ab° DR4) molecules, we demonstrated a protective effect of a HLA-DR*0401–restricted DP8α Treg clone combined with F. prausnitzii administration in a colitis model. In a cohort of patients with IBD, we showed an independent association between the frequency of circulating DP8α cells and disease activity. Finally, we pointed out a positive correlation between F. prausnitzii–specific DP8α Tregs and the amount of F. prausnitzii in fecal microbiota in healthy individuals and patients with ileal Crohn’s disease.

Summary Antimicrobial peptides secreted by intestinal immune and epithelial cells are important effectors of innate immunity. They play an essential role in the maintenance of intestinal homeostasis by limiting microbial epithelium interactions and preventing unnecessary microbe‐driven inflammation. Pancreatitis‐associated protein (PAP) belongs to Regenerating islet‐derived III proteins family and is a C‐type (Ca+2 dependent) lectin. PAP protein plays a protective effect presenting anti‐inflammatory properties able to reduce the severity of colitis, preserving gut barrier and epithelial inflammation. Here, we sought to determine whether PAP delivered at intestinal lumen by recombinant Lactococcus lactis strain (LL‐PAP) before and after chemically induced colitis is able to reduce the severity in two models of colitis. After construction and characterization of our recombinant strains, we tested their effects in dinitro‐benzenesulfonic‐acid (DNBS) and Dextran sulfate sodium (DSS) colitis model. After the DNBS challenge, mice treated with LL‐PAP presented less severe colitis compared with PBS and LL‐empty‐treated mice groups. After the DSS challenge, no protective effects of LL‐PAP could be detected. We determined that after 5 days administration, LL‐PAP increase butyrate producer's bacteria, especially Eubacterium plexicaudatum. Based on our findings, we hypothesize that a treatment with LL‐PAP shifts the microbiota preventing the severity of colon inflammation in DNBS colitis model. These protective roles of LL‐PAP in DNBS colitis model might be through intestinal microbiota modulation.

Faecalibacterium prausnitzii is abundant in the healthy human intestinal microbiota, and the absence or scarcity of this bacterium has been linked with inflammatory diseases and metabolic disorders. F. prausnitzii thus shows promise as a next-generation probiotic for use in restoring the balance of the gut microbial flora and, due to its strong anti-inflammatory properties, for the treatment of certain pathological conditions. However, very little information is available about gene function and regulation in this species. Here, we utilized a systems biology approach—weighted gene co-expression network analysis (WGCNA)–to analyze gene expression in three publicly available RNAseq datasets from F. prausnitzii strain A2-165, all obtained in different laboratory conditions. The co-expression network was then subdivided into 24 co-expression gene modules. A subsequent enrichment analysis revealed that these modules are associated with different kinds of biological processes, such as arginine, histidine, cobalamin, or fatty acid metabolism as well as bacteriophage function, molecular chaperones, stress response, or SOS response. Some genes appeared to be associated with mechanisms of protection against oxidative stress and could be essential for F. prausnitzii’s adaptation and survival under anaerobic laboratory conditions. Hub and bottleneck genes were identified by analyses of intramodular connectivity and betweenness, respectively; this highlighted the high connectivity of genes located on mobile genetic elements, which could promote the genetic evolution of F. prausnitzii within its ecological niche. This study provides the first exploration of the complex regulatory networks in F. prausnitzii, and all of the “omics” data are available online for exploration through a graphical interface at https://shiny.migale.inrae.fr/app/faeprau.

Metabolic disorders are an increasing concern in the industrialized world. Current research has shown a direct link between the composition of the gut microbiota and the pathogenesis of obesity and diabetes. In only a few weeks, an obesity-inducing diet can lead to increased gut permeability and microbial dysbiosis, which contributes to chronic inflammation in the gut and adipose tissues, and to the development of insulin resistance. In this review, we examine the interplay between gut inflammation, insulin resistance, and the gut microbiota, and discuss how some probiotic species can be used to modulate gut homeostasis. We focus primarily on Faecalibacterium prausnitzii, a highly abundant butyrate-producing bacterium that has been proposed both as a biomarker for the development of different gut pathologies and as a potential treatment due to its production of anti-inflammatory metabolites.

We appreciate the intent by Salminen et al. to clarify and reorganize the nomenclature regarding the use of inactivated bacteria and their products as health-promoting factors (Salminen, S. et al. The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nat. Rev. Gastroenterol. Hepatol. 18, 649–667 (2021))1. Nonetheless, we found several major caveats in the consensus statement (Box 1) that might generate ambiguity.

International audience; Maternal immune activation (MIA) and poor maternal nutritional habits are risk factors for the occurrence of neurodevelopmental disorders (NDD). Human studies show the deleterious impact of prenatal inflammation and low n-3 polyunsaturated fatty acid (PUFA) intake on neurodevelopment with long-lasting consequences on behavior. However, the mechanisms linking maternal nutritional status to MIA are still unclear, despite their relevance to the etiology of NDD. We demonstrate here that low maternal n-3 PUFA intake worsens MIA-induced early gut dysfunction, including modification of gut microbiota composition and higher local inflammatory reactivity. These deficits correlate with alterations of microglia-neuron crosstalk pathways and have long-lasting effects, both at transcriptional and behavioral levels. This work highlights the perinatal period as a critical time window, especially regarding the role of the gut-brain axis in neurodevelopment, elucidating the link between MIA, poor nutritional habits, and NDD. Fig. 1 EFFECT OF N-3 PUFA DEFICIENCY ON MIA-INDUCED BEHAVIORAL DEFICITS IN NEONATES AND IN ADULT OFFSPRING.: All graphs show Means ± SEM. a Experimental setup. b Average time spent by pups to achieve the Fox battery tests (negative geotaxis and righting reflex; 3 trials per day from PND4 to PND6). N = 14-19. Two-way ANOVA: MIA effect, F(1,62) = 11.67, p = 0.0011. c Average vocalization time (15-min sessions at PND7-8). N = 14-19. Kruskal-Wallis test followed by Mann-Whitney comparison; n-3 sufficient-Saline vs n-3 sufficient-LPS, **p

Every year, millions of people around the world benefit from radiation therapy to treat cancers localized in the pelvic area. Damage to healthy tissue in the radiation field can cause undesirable toxic effects leading to gastrointestinal complications called pelvic radiation disease. A change in the composition and/or function of the microbiota could contribute to radiation-induced gastrointestinal toxicity. In this study, we tested the prophylactic effect of a new generation of probiotic like Faecalibacterium prausnitzii (F. prausnitzii) on acute radiation-induced colonic lesions. Experiments were carried out in a preclinical model of pelvic radiation disease. Rats were locally irradiated at 29 Gray in the colon resulting in colonic epithelial barrier rupture. Three days before the irradiation and up to 3 d after the irradiation, the F. prausnitzii A2-165 strain was administered daily (intragastrically) to test its putative protective effects. Results showed that prophylactic F. prausnitzii treatment limits radiation-induced para-cellular hyperpermeability, as well as the infiltration of neutrophils (MPO+ cells) in the colonic mucosa. Moreover, F. prausnitzii treatment reduced the severity of the morphological change of crypts, but also preserved the pool of Sox-9+ stem/progenitor cells, the proliferating epithelial PCNA+ crypt cells and the Dclk1+/IL-25+ differentiated epithelial tuft cells. The benefit of F. prausnitzii was associated with increased production of IL-18 by colonic crypt epithelial cells. Thus, F. prausnitzii treatment protected the epithelial colonic barrier from colorectal irradiation. New-generation probiotics may be promising prophylactic treatments to reduce acute side effects in patients treated with radiation therapy and may improve their quality of life.

Introduction et but de l’etude La sarcopenie peut etre expliquee partiellement par le developpement d’une resistance anabolique au repas. La presence d’une inflammation bas bruit systemique est un des facteurs potentiellement responsable de cette resistance. Elle pourrait prendre son origine au niveau intestinal avec une augmentation de la permeabilite du tissu digestif associee a l’etablissement d’une dysbiose du microbiote intestinal au cours du vieillissement. L’objectif de notre etude est donc de tester in vivo sur des animaux âges avec une inflammation intestinale bas bruit, l’effet protecteur vis a vis du muscle squelettique, d’une souche bacterienne (CNRZ 160) presentant des proprietes anti-inflammatoires validees in vitro (Junjua et al., 2016). Materiel et methodes L’inflammation intestinale bas bruit a ete induite a des rats âges (18 m) par ingestion de DSS (4 % p/v) dans l’eau de boisson pendant 28j avec ou sans une dose quotidienne de S. Thermophilus CNRZ160 (109 CFU/j). Ils ont ete compares a des rats temoins recevant la meme quantite de nourriture (PF). Le poids corporel et l’ingere ont ete suivis quotidiennement, la masse maigre et la masse grasse mesurees par EchoMRI a J0, J14 et J28 et les poids de muscles et colon mesures a J28 au sacrifice. La synthese proteique musculaire et du colon sont mesurees par surcharge de valine (13C). L’analyse statistique est une ANOVA 1 facteur et test posthoc Fisher. Significativite : p Resultats et analyse statistique Pour les animaux DSS, la perte de poids corporelle, de masse maigre et grasse a J28 est significativement plus importante que celle des temoins PF (−110 vs −86 g ; −51 vs −36 g et −65 vs −47 g, respectivement, p Conclusion Une inflammation intestinale bas bruit peut etre a l’origine d’une diminution de proteosynthese musculaire et sur le long terme participer a linstallation de la sarcopenie. Le mecanismes mis en jeu pourraient etre une competition dans l’utilisation des nutriments entre intestin et muscle car la synthese proteique du colon est fortement augmentee. Avec l’ingestion d’un probiotique aux proprietes anti inflammatoires, il a ete possible de limiter cette competition, en maintenant une proteosynthese colique normale, et donc de maintenir un apport en acides amines au muscle favorable au maintien de la synthese proteique. Une mesure de l’inflammation systemique et de l’intestin est en cours pour affiner les mecanismes d’action du CNRZ160.

National audience; Introduction et but de l’étude: La sarcopénie peut être expliquée partiellement par le développement d’une résistance anabolique au repas. La présence d’une inflammation bas bruit systémique est un des facteurs potentiellement responsablede cette résistance. Elle pourrait prendre son origine au niveau intestinal avec une augmentation de la perméabilité du tissu digestif associée à l’établissement d’une dysbiose du microbiote intestinal au cours du vieillissement. L’objectif de notre étude est donc de tester in vivo sur des animaux âgés avec une inflammation intestinale bas bruit, l’effetprotecteur vis a vis du muscle squelettique,d’une souche bactérienne (CNRZ 160) présentant des propriétés anti-inflammatoires validées in vitro (Junjua et al, 2016) Matériel et méthodes: L'inflammationintestinale bas bruit a été induite à des rats âgés (18m) par ingestion de DSS (4% p/v) dans l’eau de boisson pendant 28j avec ou sans une dose quotidienne deS. Thermophilus CNRZ160(109 CFU/j). Ils ont été comparés à des rats témoins recevant la même quantité de nourriture (PF). Le poids corporel et l’ingéré ont été suivis quotidiennement, la masse maigre et la masse grasse mesurées par EchoMRI à J0, J14 et J28 et les poids de muscles et colon mesurés à J28 au sacrifice. La synthèse protéique musculaire et du colon sont mesurées par surcharge de valine (13C). L’analyse statistique est une ANOVA 1 facteur et test posthoc Fisher. Significativité: p

ICTRHN Nutrition, Physical activity and health Oral communication SESSION 4: GUT MICROBIOTA, NUTRITION AND MOBILITY ICTRHN Nutrition, Physical activity and health Oral communication SESSION 4: GUT MICROBIOTA, NUTRITION AND MOBILITYICTRNH Nutrition, Physical activity and healthOral communication SESSION 4: GUT MICROBIOTA, NUTRITION AND MOBILITY; During low-grade intestinal inflammation, ingestion of Streptococcus Thermophilus CNRZ160 Limited the Lean Body Mass Loss in Older Adults. Fifth International Congress of Translational Research in Human Nutrition (ICTRHN)

B-type oligomeric procyanidins in apples constitute an important source of polyphenols in the human diet. Their role in health is not known, although it is suggested that they generate beneficial bioactive compounds upon metabolization by the gut microbiota. During apple processing, procyanidins interact with cell-wall polysaccharides and form stable complexes. These interactions need to be taken into consideration in order to better assess the biological effects of fruit constituents. Our objectives were to evaluate the impact of these interactions on the microbial metabolization of cell walls and procyanidins, and to investigate the potential anti-inflammatory activity of the resulting metabolome, in addition to analyzing the taxonomical changes which the microbiota undergo. In vitro fermentation of three model apple matrices with microbiota from 4 healthy donors showed that the binding of procyanidins to cell-wall polysaccharides, whether covalently or non-covalently, substantially reduced procyanidin degradation. Although cell wall-unbound procyanidins negatively affected carbohydrate fermentation, they generated more hydroxyphenylvaleric acid than bound procyanidins, and increased the abundance of Adlercreutzia and Gordonibacter genera. The best results in terms of production of anti-inflammatory bioactive metabolites were observed from the apple matrix with no bonds between procyanidins and cell wall polysaccharides, although the matrix with non-covalent bonds was not far behind.

Phallus atrovolvatus is a wild edible mushroom which is recently being cultivated in Thailand. It contains a remarkable amount of β-(1,3–1,6)-glucan, a compound known for its immune modulating properties. Crude mushroom polysaccharide (CMP) was obtained from the fruiting body of P. atrovolvatus using boiling water extraction, followed by overnight ethanol cold precipitation. CMP is composed of approximately 50% β-glucan, α-glucan, proteins, ash and other non-digestible polysaccharide. In this study, we evaluated the immune modulating activities of CMP using in vitro and in vivo models. In vitro, CMP was treated with the transfected NF-κB reporter-HEK 293 recombinant cell line, the results showed no cytotoxicity up to 500 μg/mL, and CMP treatments exhibited a higher % NF-κB luciferase expression. DiNitroBenzene Sulfonic acid (DNBS)-induced colitis mice model was used to elucidate the effects of CMP in vivo. Colitis severity was assessed using body weight trend, macroscopic scores and histological scores. Myeloperoxidase (MPO) activity and cytokine production were determined from the colon tissue and spleen, respectively. The results showed that oral consumption of 50 μg CMP/mouse/day could significantly decrease MPO activity and reduce the secretion of TNF-α, IL-6, IL-10, and IL-17A cytokines. To our knowledge, this study shows the first time the report of immune modulating activities of Phallus atrovolvatus Thai strain. The results lead to the conclusion that CMP provides two modes of actions: i) stimulating the NF-κB pathway and ii) acting as an anti-inflammatory that can protect mice against induced colitis.

International audience; Two recent papers show that probiotics colonize the gut in permissive volunteers only and delay the reconstitution of the microbiome after antibiotics treatment. In the absence of any clinical readouts, it is still difficult to extrapolate these observations in terms of short-term or long-term health consequences for patients.

Background The intestinal microbiota of patients with Crohn’s disease (CD) is characterised by a specific dysbiosis, including the loss of Faecalibacterium prausnitzii (F. prau), a major bacterium with anti-inflammatory properties. MAM protein (microbiotia anti-inflammatory molecule) produced by F. prau has recently been identified as partially carrying the anti-inflammatory activity of this bacterium. The description of microbiota for diagnostic purposes in CD is currently difficult to achieve. MAM could be a biomarker of dysbiosis. Our goal was to study the expression of MAM in the intestinal ecosystem and to evaluate its interest as a biomarker. Methods An in silico approach was used to determine primers of MAM gene sequences specific to two currently known phylogroups (I and II) of F. prau. Faecal samples were collected from a monocentric cohort of CD patients in flare (n = 24) and in remission (n = 24) and from healthy controls (n = 12). To measure MAM expression in vivo in the microbiota, we extracted total RNA and DNA from each sample and performed quantitative PCR (qPCR) with MAM primers (I and II), F. prau primers and universal bacterial primers. We compared the relative expression (ΔCt) of MAM mRNA and DNA with qPCR to the overall amount of bacteria in faecal samples. Results MAM analyses of F. prau phylogroup II were the most informative. We observed that the relative expression of MAM mRNA was statistically lower in active patients 5.84 × 10−5 [95% CI 3.8 × 10−6–2.1 × 10−3] and in remission 5.36 × 10−5 [95% CI 2.5 × 10−8–1.9 × 10−2] compared with healthy controls 5.42 × 10−4 [95% CI 8.5 × 10−5–9.1 × 10−2], (p = 0.004). There was no difference in ΔCt between flare and remission in CD patients. The most relevant relative expression threshold was 1.6 × 10−4. At this threshold, sensitivity was 81%, specificity 76%, positive predictive value 94% and negative predictive value 47%. In multivariate analysis, the relative expression of MAM was an independently associated with the diagnosis of CD; OR 2.961 [95% CI 2.026–4.831] (p = 0.003). Using relative expression of MAM DNA, we found a significant decrease in the flare group compared with remission patients and controls. We found a negative correlation of MAM DNA expression with CRP (p = 0.0053) and HBI (p = 0.025). Conclusion Our results showed that the loss of MAM RNA expression is observed in CD patients. Moreover, MAM DNA detection was associated with CD activity parameters. This opens up the prospect of an ecological biomarker of CD based on the expression of molecules from the intestinal ecosystem. These results will need to be validated in larger independent cohorts and their specificities compared with other pathological situations.

Mucositis is an inflammatory condition of the gut, caused by an adverse effect of chemotherapy drugs, such as 5-fluorouracil (5-FU). In an attempt to develop alternative treatments for the disease, several research groups have proposed the use of probiotics, in particular, Lactic Acid Bacteria (LAB). In this context, the use of recombinant LAB, for delivering anti-inflammatory compounds has also been explored. In previous work, we demonstrated that either Lactococcus lactis NZ9000 or a recombinant strain expressing an antimicrobial peptide involved in human gut homeostasis, the Pancreatitis-associated Protein (PAP), could ameliorate 5-FU-induced mucositis in mice. However, the impact of these strains on the gut microbiota still needs to be elucidated. Therefore, in the present study, we aimed to characterize the effects of both Lactococci strains in the gut microbiome of mice through a 16 S rRNA gene sequencing metagenomic approach. Our data show 5-FU caused a significant decrease in protective bacteria and increase of several bacteria associated with pro-inflammatory traits. The Lactococci strains were shown to reduce several potential opportunistic microbes, while PAP delivery was able to suppress the growth of Enterobacteriaceae during inflammation. We conclude the strain secreting antimicrobial PAP was more effective in the control of 5-FU-dysbiosis.

ObjectiveLoss of the Crohn’s disease predisposing NOD2 gene results in an intestinal microenvironment conducive for colonisation by attaching-and-effacing enteropathogens. However, it remains elusive whether it relies on the intracellular recruitment of the serine-threonine kinase RIPK2 by NOD2, a step that is required for its activation of the transcription factor NF-κB.DesignColonisation resistance was evaluated in wild type and mutant mice, as well as in ex-germ-free (ex-GF) mice which were colonised either with faeces from Ripk2-deficient mice or with bacteria with similar preferences for carbohydrates to those acquired by the pathogen. The severity of the mucosal pathology was quantified at several time points postinfection by using a previously established scoring. The community resilience in response to infection was evaluated by 16S ribosomal RNA gene sequence analysis. The control of pathogen virulence was evaluated by monitoring the secretion of Citrobacter-specific antibody response in the faeces.ResultsPrimary infection was similarly outcompeted in ex-GF Ripk2-deficient and control mice, demonstrating that the susceptibility to infection resulting from RIPK2 deficiency cannot be solely attributed to specific microbiota community structures. In contrast, delayed clearance of Citrobacter rodentium and exacerbated histopathology were preceded by a weakened propensity of intestinal macrophages to afford innate lymphoid cell activation. This tissue protection unexpectedly required the regenerating family member 3β by instigating interleukin (IL) 17A-mediated neutrophil recruitment to the intestine and subsequent phosphorylation of signal transducer and activator of transcription 3.ConclusionsThese results unveil a previously unrecognised mechanism that efficiently protects from colonisation by diarrhoeagenic bacteria early in infection.

Le laboratoire international associe (LIA) Bact-Inflam, dedie a l’etude des bacteries et des maladies inflammatoires en sante humaine et animale, offre un exemple exceptionnel de cooperation reussie entre le Bresil et la France depuis le debut du XXIe siecle.

International audience; Lactic acid bacteria as Lactococcus lactis are used as vector for protein but also DNA delivery into intestinal cells in vitro and in vivo. For the plasmid delivery strategy, the plasmid copy number per bacteria (PCN) is thus of great importance. The aim of this paper is to determine the physiological conditions when PCN is the highest in the bacteria. PCN was characterized by qPCR in five different recombinant Lactococcus lactis strains, containing one (mono-) or two different plasmids (biplasmidic), at exponential or stationary phase. We showed that in all cases but one, PCN is higher at exponential than stationary phase. PCN seems to depend on (i) monoplasmidic or biplasmidic strain; (ii) origin of replication of the plasmid; and (iii) the DNA load of the bacteria. Then we studied plasmid transfer in vitro from recombinant L. lactis to eukaryotic COS-7 cells using culture at exponential or stationary phase. We showed that plasmid transfer can be improved in vitro by using bacteria at exponential phase.

During low-grade intestinal inflammation, ingestion of Streptococcus Thermophilus CNRZ160 Limited the Lean Body Mass Loss in Older Adults . 41. ESPEN Congress

Allergic diseases affect up to 30% of the western population, and their prevalence is increasing. Probiotics are able to modulate the mucosal immune response, and clinical trials demonstrated that specific strains, especially lactic acid bacteria (LAB) ones, reduce allergic symptoms. Moreover, the use of recombinant probiotics has been evaluated as possible strategies for the immunotherapy of allergic diseases. The production and delivery of allergens by recombinant LAB in concert with their ability to induce a Th1-type immune response have been shown to be a promising mucosal vaccination strategy in mouse model. The aim of this article is to review the applications of probiotics in allergy immunotherapy with a special focus on recombinant LAB delivering proteins or DNA.

The human gastrointestinal tract (GIT) is highly colonized by bacterial communities, which live in a symbiotic relationship with the host in normal conditions. It has been shown that a dysfunctional interaction between the intestinal microbiota and the host immune system, known as dysbiosis, is a very important factor responsible for the development of different inflammatory conditions of the GIT, such as the idiopathic inflammatory bowel diseases (IBD), a complex and multifactorial disorder of the GIT. Dysbiosis has also been implicated in the pathogenesis of other GIT inflammatory diseases such as mucositis usually caused as an adverse effect of chemotherapy. As both diseases have become a great clinical problem, many research groups have been focusing on developing new strategies for the treatment of IBD and mucositis. In this review, we show that lactic acid bacteria (LAB) have been capable in preventing and treating both disorders in animal models, suggesting they may be ready for clinical trials. In addition, we present the most current studies on the use of wild type or genetically engineered LAB strains designed to express anti-inflammatory proteins as a promising strategy in the treatment of IBD and mucositis.

Thymic stromal lymphopoietin (TSLP) is a cytokine known to mature dendritics cells, lower pro-inflammatory IL-12 secretion, induce differentiation of anti-inflammatory FoxP3+ regulatory T cells (Treg). Moreover, Crohn's disease patients have shown a reduction of intestinal TSLP expression. To understand the role of TSLP in inflammation, we constructed Lactococcus lactis strain producing TSLP (LL-TSLP) and investigated the effect of its administration on dextran sulfate sodium (DSS)-induced colitis model in mice.LL-TSLP secrete an active molecule which lowers secretion of IL-12 by dendritic cells. Treatment with LL-TSLP, increases the amount of TGF-β secreted by T cells in Mesenteric Lymph Node in healthy mice. In acute DSS-induced colitis, LL-TSLP delayed the Disease Activity Index and lowered histological score and colonic INF-γ production. In a DSS-recovery model, LL-TSLP induced a better protective effect if the strain was administered at the beginning of the colitis. At Day 4 of colitis we observed an induction of Treg by LL-TSLP.TSLP showed an anti-inflammatory protective role in DSS-induced colitis. We have demonstrated that a short and early administration of LL-TSLP is more efficient than a long lasting treatment.

Objectif de l’etude La radiotherapie est le traitement incontournable dans la prise en charge de cancers dans la zone pelvienne. L’irradiation des tissus environnant la tumeur entraine des effets secondaires plusieurs annees apres la fin de la radiotherapie. Une nouvelle pathologie, la pelvic radiation disease, a ete definie en 2010, suite au nombre croissant de patients souffrant de complications tardives. Elles ont pour origine le declenchement d’une forte reponse inflammatoire due a la perte de l’integrite d’organes tres radiosensibles (colon et rectum). Une modification de la diversite du microbiote intestinal est observee apres radiotherapie, notamment une diminution des populations de Faecalibacterium prausnitzii, qui joue un role important dans le maintien de la barriere intestinale. Au Laboratoire de radiobiologie des expositions medicales (LRMed), un effet therapeutique des cellules stromales mesenchymateuses a ete demontre dans un modele d’ulceration radio-induite du colon. Cet effet est cependant partiel sur des ulcerations severes. Cette etude, en collaboration avec l’Institut national de la recherche agronomique (Inra), avait pour objectif de potentialiser cette therapie cellulaire, en associant F. prausnitzii aux cellules stromales mesenchymateuses. Le premier objectif etait d’analyser la capacite de F. prausnitzii a prevenir l’apparition d’ulcerations severes coliques radio-induites. Materiel et methode L’effet de l’administration quotidienne de 109 colony forming units (CFU) de F. prausnitzii a ete etudie 72 h apres une irradiation colorectale de 29 Gy. Le traitement commencait 3 jours avant l’irradiation et se terminait a l’euthanasie des animaux. L’integrite de la barriere colique a ete evaluee par analyse histologique pour observer les alterations et l’etat de renouvellement de l’epithelium. Resultats L’administration de F. prausnitzii semble montrer une diminution des dommages radio-induits de la muqueuse colique. Ce traitement reduit les zones de cryptes atypiques, augmente la capacite proliferative des cellules epitheliales et les cellules exprimant SOX9. Conclusion Ces resultats preliminaires suggerent que l’administration de F. prausnitzii permet de diminuer les dommages de l’epithelium colique et d’ameliorer sa fonction de barriere.

Lactococci are noninvasive bacteria frequently used as protein delivery vectors and, more recently, as in vitro and in vivo DNA delivery vehicles. We previously showed that a functional eukaryotic enhanced green fluorescent protein (eGFP) expression plasmid vector was delivered in epithelial cells by Lactococcus lactis producing Listeria monocytogenes internalin A ( L. lactis InlA + ), but this strategy is limited in vivo to transgenic mice and guinea pigs. In this study, we compare the internalization ability of L. lactis InlA + and L. lactis producing either the fibronectin-binding protein A of Staphylococcus aureus ( L. lactis FnBPA + ) or its fibronectin binding domains C and D ( L. lactis CD + ). L. lactis FnBPA + and L. lactis InlA + showed comparable internalization rates in Caco-2 cells, while the internalization rate observed with L. lactis CD + was lower. As visualized by conventional and confocal fluorescence microscopy, large clusters of L. lactis FnBPA + , L. lactis CD + , and L. lactis InlA + were present in the cytoplasm of Caco-2 cells after internalization. Moreover, the internalization rates of Lactobacillus acidophilus NCFM and of an NCFM mutant strain with the gene coding for the fibronectin-binding protein ( fbpA ) inactivated were also evaluated in Caco-2 cells. Similar low internalization rates were observed for both wild-type L. acidophilus NCFM and the fbpA mutant, suggesting that commensal fibronectin binding proteins have a role in adhesion but not in invasion. L. lactis FnBPA + , L. lactis CD + , and L. lactis InlA + were then used to deliver a eukaryotic eGFP expression plasmid in Caco-2 cells: flow cytometry analysis showed that the highest percentage of green fluorescent Caco-2 cells was observed after coculture with either L. lactis FnBPA + or L. lactis InlA + . Analysis of the in vivo efficiency of these invasive recombinant strains is currently in progress to validate their potential as DNA vaccine delivery vehicles.

In this study, Lactococcus lactis was engineered to express mutated internalin A on its surface and to secrete large amounts of listeriolysin O (LLO) in order to improve its potential as a vehicle for DNA vaccination. Western blotting experiments demonstrated that the bacterium expressed LLO in both the cytoplasmic and extracellular compartments, with higher quantities found in the culture supernatants. A hemolytic assay showed that the recombinant strain secreted 250 ng active LLO/mg total protein. This mInlA/LLO-producing strain of L. lactis may be used as an alternative tool in DNA vaccination against a number of infectious diseases or in cancer therapy. Fil: de Azevedo, M. S. P.. Universidade Federal de Minas Gerais; Brasil Fil: Santos Rocha, C.. Universidade Federal de Minas Gerais; Brasil Fil: Pereira, V. B.. Universidade Federal de Minas Gerais; Brasil Fil: de Oliveira Junior, A. .. Universidade Federal de Minas Gerais; Brasil Fil: de Sousa, C. S.. Universidade Federal de Minas Gerais; Brasil Fil: Azevedo, V.. Universidade Federal de Minas Gerais; Brasil Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Chatel, J. M.. Institut National de la Recherche Agronomique; Francia Fil: Miyoshi, A.. Universidade Federal de Minas Gerais; Brasil

A recombinant strain of Lactococcus lactis displaying a cell-surface anchored fibronectin binding protein A (FnBPA) from Staphylococcus aureus (LL-FnBPA) had been shown to be more efficient in delivering plasmid than its wild-type counterpart both in vitro and in vivo, and have the ability to orientate the immune response toward a Th2 profile in a context of a DNA vaccination. The aim of this work was to test whether this LL-FnBPA strain could shape the immune response after mucosal administration in mice. For this, we used a mouse model of human papilloma virus (HPV)-induced cancer and a L. lactis strain displaying at its cell surface both HPV-16-E7 antigen (LL-E7) and FnBPA (LL-E7 + FnBPA). Our results revealed a more efficient systemic Th1 immune response with recombinant LL-E7 + FnBPA. Furthermore, mice vaccinated with LL-E7 + FnBPA were better protected when challenged with HPV-16-induced tumors. Altogether, the results suggest that FnBPA displays adjuvant properties when used in the context of mucosal delivery using L. lactis as a live vector. (C) 2016 Published by Elsevier Ltd.