RESUMO
Lipidomic techniques can improve our understanding of complex lipid interactions that regulate metabolic diseases. Here, a serum phospholipidomics analysis identified associations between phosphatidylglycerols (PGs) and gut microbiota dysbiosis. Compared with the other phospholipids, serum PGs were the most elevated in patients with low microbiota gene richness, which were normalized after a dietary intervention that restored gut microbial diversity. Serum PG levels were positively correlated with metagenomic functional capacities for bacterial LPS synthesis and host markers of low-grade inflammation; transcriptome databases identified PG synthase, the first committed enzyme in PG synthesis, as a potential mediator. Experiments in mice and cultured human-derived macrophages demonstrated that LPS induces PG release. Acute PG treatment in mice altered adipose tissue gene expression toward remodeling and inhibited ex vivo lipolysis in adipose tissue, suggesting that PGs favor lipid storage. Indeed, several PG species were associated with the severity of obesity in mice and humans. Finally, despite enrichment in PGs in bacterial membranes, experiments employing gnotobiotic mice colonized with recombinant PG overproducing Lactococcus lactis showed limited direct contribution of microbial PGs to the host. In summary, PGs are inflammation-responsive lipids indirectly regulated by the gut microbiota via endotoxins and regulate adipose tissue homeostasis in obesity.-Kayser, B. D., Lhomme, M., Prifti, E., Da Cunha, C., Marquet, F., Chain, F., Naas, I., Pelloux, V., Dao, M.-C., Kontush, A., Rizkalla, S. W., Aron-Wisnewsky, J., Bermúdez-Humarán, L. G., Oakley, F., Langella, P., Clément, K., Dugail, I. Phosphatidylglycerols are induced by gut dysbiosis and inflammation, and favorably modulate adipose tissue remodeling in obesity.
Assuntos
Tecido Adiposo/metabolismo , Disbiose/metabolismo , Inflamação/metabolismo , Obesidade/metabolismo , Fosfatidilgliceróis/metabolismo , Animais , Feminino , Humanos , Lipidômica/métodos , Lipólise/fisiologia , Masculino , Metagenômica/métodos , CamundongosRESUMO
Bacteroides thetaiotaomicron is a prominent anaerobic member of the healthy human gut microbiota. While the majority of functional studies on B. thetaiotaomicron addressed its impact on the immune system and the utilization of diet polysaccharides, B. thetaiotaomicron biofilm capacity and its contribution to intestinal colonization are still poorly characterized. We tested the natural adhesion of 34 B. thetaiotaomicron isolates and showed that although biofilm capacity is widespread among B. thetaiotaomicron strains, this phenotype is masked or repressed in the widely used reference strain VPI 5482. Using transposon mutagenesis followed by a biofilm positive-selection procedure, we identified VPI 5482 mutants with increased biofilm capacity corresponding to an alteration in the C-terminal region of BT3147, encoded by the BT3148-BT3147 locus, which displays homology with Mfa-like type V pili found in many Bacteroidetes We show that BT3147 is exposed on the B. thetaiotaomicron surface and that BT3147-dependent adhesion also requires BT3148, suggesting that BT3148 and BT3147 correspond to the anchor and stalk subunits of a new type V pilus involved in B. thetaiotaomicron adhesion. This study therefore introduces B. thetaiotaomicron as a model to study proteinaceous adhesins and biofilm-related phenotypes in this important intestinal symbiont.IMPORTANCE Although the gut anaerobe Bacteroides thetaiotaomicron is a prominent member of the healthy human gut microbiota, little is known about its capacity to adhere to surfaces and form biofilms. Here, we identify that alteration of a surface-exposed protein corresponding to a type of pili found in many Bacteroidetes increases B. thetaiotaomicron biofilm formation. This study lays the ground for establishing this bacterium as a model organism for in vitro and in vivo studies of biofilm-related phenotypes in gut anaerobes.
Assuntos
Bacteroides thetaiotaomicron/fisiologia , Biofilmes/crescimento & desenvolvimento , Fímbrias Bacterianas/fisiologia , Animais , Aderência Bacteriana/fisiologia , Microbioma Gastrointestinal/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C3HRESUMO
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.
Assuntos
Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Colite/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Lactococcus lactis/metabolismo , Proteínas Associadas a Pancreatite/uso terapêutico , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Benzenossulfonatos/toxicidade , Colite/induzido quimicamente , Colite/patologia , Colo/metabolismo , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas a Pancreatite/metabolismo , Peptídeos/metabolismoRESUMO
The aim of this review is to summarize the effect in host energy metabolism of the production of B group vitamins and short chain fatty acids (SCFA) by commensal, food-grade and probiotic bacteria, which are also actors of the mammalian nutrition. The mechanisms of how these microbial end products, produced by these bacterial strains, act on energy metabolism will be discussed. We will show that these vitamins and SCFA producing bacteria could be used as tools to recover energy intakes by either optimizing ATP production from foods or by the fermentation of certain fibers in the gastrointestinal tract (GIT). Original data are also presented in this work where SCFA (acetate, butyrate and propionate) and B group vitamins (riboflavin, folate and thiamine) production was determined for selected probiotic bacteria.
Assuntos
Metabolismo Energético , Ácidos Graxos Voláteis/metabolismo , Probióticos/metabolismo , Simbiose , Vitaminas/metabolismo , Trifosfato de Adenosina/biossíntese , Trifosfato de Adenosina/metabolismo , Animais , Butiratos/metabolismo , Fibras na Dieta/metabolismo , Ácidos Graxos Voláteis/biossíntese , Fermentação , Alimentos , Microbioma Gastrointestinal/fisiologia , Trato Gastrointestinal/microbiologia , Humanos , Camundongos , Vitaminas/biossínteseRESUMO
Inorganic complexes are increasingly used for biological and medicinal applications, and the question of the cell penetration and distribution of metallodrugs is key to understanding their biological activity. Oxidative stress is known to be involved in inflammation and in inflammatory bowel diseases for which antioxidative defenses are weakened. We report here the study of the manganese complex Mn1 mimicking superoxide dismutase (SOD), a protein involved in cell protection against oxidative stress, using an approach in inorganic cellular chemistry combining the investigation of Mn1 intracellular speciation using mass spectrometry and of its quantification and distribution using electron paramagnetic resonance and spatially resolved X-ray fluorescence with evaluation of its biological activity. More precisely, we have looked for and found the MS signature of Mn1 in cell lysates and quantified the overall manganese content. Intestinal epithelial cells activated by bacterial lipopolysaccharide were taken as a cellular model of oxidative stress and inflammation. DNBS-induced colitis in mice was used to investigate Mn1 activity in vivo. Mn1 exerts an intracellular antiinflammatory activity, remains at least partially coordinated, with diffuse distribution over the whole cell, and functionally complements mitochondrial MnSOD.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Colite/tratamento farmacológico , Modelos Animais de Doenças , Doenças Inflamatórias Intestinais/tratamento farmacológico , Compostos Organometálicos/farmacologia , Superóxido Dismutase/metabolismo , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Quimiocinas/antagonistas & inibidores , Quimiocinas/metabolismo , Colite/induzido quimicamente , Colite/metabolismo , Dinitrofluorbenzeno/análogos & derivados , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Compostos Organometálicos/química , Compostos Organometálicos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/químicaRESUMO
The ability of Lactococcus lactis to adhere to the intestinal mucosa can potentially prolong the contact with the host, and therefore favour its persistence in the gut. In the present study, the contribution of plasmid-encoded factors to the adhesive and transit properties of the L. lactis subsp. cremoris IBB477 strain was investigated. Plasmid-cured derivatives as well as deletion mutants were obtained and analysed. Adhesion tests were performed using non-coated polystyrene plates, plates coated with mucin or fibronectin and mucus-secreting HT29-MTX intestinal epithelial cells. The results indicate that two plasmids, pIBB477a and b, are involved in adhesion of the IBB477 strain. One of the genes localised on plasmid pIBB477b (AJ89_14230), which encodes cell wall-associated peptidase S8 (PrtP), mediates adhesion of the IBB477 strain to bare, mucin- and fibronectin-coated polystyrene, as well as to HT29-MTX cells. Interactions between bacteria and mucus secreted by HT29-MTX cells were further investigated by fluorescent staining and confocal microscopy. Confocal images showed that IBB477 forms dense clusters embedded in secreted mucus. Finally, the ability of IBB477 strain and its ΔprtP deletion mutant to colonise the gastrointestinal tract of conventional C57Bl/6 mice was determined. Both strains were present in the gut for up to 72 h. In summary, adhesion and persistence of IBB477 were analysed by in vitro and in vivo approaches, respectively. Our studies revealed that plasmidic genes encoding cell surface proteins are more involved in the adhesion of IBB477 strain than in the ability to confer a selective advantage in the gut.
Assuntos
Aderência Bacteriana , Proteínas de Bactérias/metabolismo , Células Epiteliais/microbiologia , Mucosa Intestinal/microbiologia , Lactococcus lactis/enzimologia , Peptídeo Hidrolases/metabolismo , Plasmídeos/genética , Animais , Proteínas de Bactérias/genética , Células HT29 , Humanos , Mucosa Intestinal/citologia , Lactococcus lactis/genética , Lactococcus lactis/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Muco/microbiologia , Peptídeo Hidrolases/genética , Deleção de SequênciaRESUMO
BACKGROUND: The human gut houses one of the most complex and abundant ecosystems composed of up to 10(13)-10(14) microorganisms. The importance of this intestinal microbiota is highlighted when a disruption of the intestinal ecosystem equilibrium appears (a phenomenon called dysbiosis) leading to an illness status, such as inflammatory bowel diseases (IBD). Indeed, the reduction of the commensal bacterium Faecalibacterium prausnitzii (one of the most prevalent intestinal bacterial species in healthy adults) has been correlated with several diseases, including IBD, and most importantly, it has been shown that this bacterium has anti-inflammatory and protective effects in pre-clinical models of colitis. Some dysbiosis disorders are characterized by functional and physiological alterations. Here, we report the beneficial effects of F. prausnitzii in the physiological changes induced by a chronic low-grade inflammation in a murine model. Chronic low-grade inflammation and gut dysfunction were induced in mice by two episodes of dinitro-benzene sulfonic acid (DNBS) instillations. Markers of inflammation, gut permeability, colonic serotonin and cytokine levels were studied. The effects of F. prausnitzii strain A2-165 and its culture supernatant (SN) were then investigated. RESULTS: No significant differences were observed in classical inflammation markers confirming that inflammation was subclinical. However, gut permeability, colonic serotonin levels and the colonic levels of the cytokines IL-6, INF-γ, IL-4 and IL-22 were higher in DNBS-treated than in untreated mice. Importantly, mice treated with either F. prausnitzii or its SN exhibited significant decreases in intestinal permeability, tissue cytokines and serotonin levels. CONCLUSIONS: Our results show that F. prausnitzii and its SN had beneficial effects on intestinal epithelial barrier impairment in a chronic low-grade inflammation model. These observations confirm the potential of this bacterium as a novel probiotic treatment in the management of gut dysfunction and low-grade inflammation.
Assuntos
Clostridiales/imunologia , Enterite/patologia , Enterite/prevenção & controle , Animais , Benzenossulfonatos/toxicidade , Colo/patologia , Citocinas/análise , Modelos Animais de Doenças , Enterite/induzido quimicamente , Camundongos , Permeabilidade , Serotonina/análiseRESUMO
BACKGROUND: 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. RESULTS: LL-TSLP secrete an active molecule which lowers secretion of IL-12 by dendritic cells. Treatment with LL-TSLP, increases the amount of TGF-ß 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. CONCLUSIONS: 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.
Assuntos
Citocinas/metabolismo , Administração Oral , Animais , Colite/induzido quimicamente , Colite/patologia , Colite/prevenção & controle , Colo/metabolismo , Colo/patologia , Citocinas/genética , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Inflamação/prevenção & controle , Interleucina-12/metabolismo , Mucosa Intestinal/microbiologia , Lactococcus lactis/metabolismo , Linfonodos/citologia , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Linfopoietina do Estroma do TimoRESUMO
The aims of this study were to develop strains of lactic acid bacteria (LAB) having both immunomodulatory and antioxidant properties and to evaluate their anti-inflammatory effects both in vitro, in different cellular models, and in vivo, in a mouse model of colitis. Different Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were cocultured with primary cultures of mononuclear cells. Analysis of the pro- and anti-inflammatory cytokines secreted by these cells after coincubation with candidate bacteria revealed that L. delbrueckii subsp. bulgaricus CRL 864 and S. thermophilus CRL 807 display the highest anti-inflammatory profiles in vitro. Moreover, these results were confirmed in vivo by the determination of the cytokine profiles in large intestine samples of mice fed with these strains. S. thermophilus CRL 807 was then transformed with two different plasmids harboring the genes encoding catalase (CAT) or superoxide dismutase (SOD) antioxidant enzymes, and the anti-inflammatory effects of recombinant streptococci were evaluated in a mouse model of colitis induced by trinitrobenzenesulfonic acid (TNBS). Our results showed a decrease in weight loss, lower liver microbial translocation, lower macroscopic and microscopic damage scores, and modulation of the cytokine production in the large intestines of mice treated with either CAT- or SOD-producing streptococci compared to those in mice treated with the wild-type strain or control mice without any treatment. Furthermore, the greatest anti-inflammatory activity was observed in mice receiving a mixture of both CAT- and SOD-producing streptococci. The addition of L. delbrueckii subsp. bulgaricus CRL 864 to this mixture did not improve their beneficial effects. These findings show that genetically engineering a candidate bacterium (e.g., S. thermophilus CRL 807) with intrinsic immunomodulatory properties by introducing a gene expressing an antioxidant enzyme enhances its anti-inflammatory activities.
Assuntos
Antioxidantes/metabolismo , Fatores Imunológicos/metabolismo , Inflamação/imunologia , Engenharia Metabólica , Streptococcus thermophilus/imunologia , Animais , Catalase/genética , Catalase/metabolismo , Células Cultivadas , Colite/induzido quimicamente , Colite/imunologia , Colite/microbiologia , Colite/patologia , Citocinas/metabolismo , Modelos Animais de Doenças , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/microbiologia , Camundongos , Streptococcus thermophilus/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Ácido Trinitrobenzenossulfônico/administração & dosagem , Ácido Trinitrobenzenossulfônico/toxicidadeRESUMO
In this study, we developed a large-scale screening of bacterial strains in order to identify novel candidate probiotics with immunomodulatory properties. For this, 158 strains, including a majority of lactic acid bacteria (LAB), were screened by two different cellular models: tumor necrosis factor alpha (TNF-α)-activated HT-29 cells and peripheral blood mononuclear cells (PBMCs). Different strains responsive to both models (pro- and anti-inflammatory strains) were selected, and their protective effects were tested in vivo in a murine model of influenza virus infection. Daily intragastric administrations during 10 days before and 10 days after viral challenge (100 PFU of influenza virus H1N1 strain A Puerto Rico/8/1934 [A/PR8/34]/mouse) of Lactobacillus plantarum CNRZ1997, one potentially proinflammatory probiotic strain, led to a significant improvement in mouse health by reducing weight loss, alleviating clinical symptoms, and inhibiting significantly virus proliferation in lungs. In conclusion, in this study, we have combined two cellular models to allow the screening of a large number of LAB for their immunomodulatory properties. Moreover, we identified a novel candidate probiotic strain, L. plantarum CNRZ1997, active against influenza virus infection in mice.
Assuntos
Fatores Imunológicos/administração & dosagem , Lactobacillus plantarum/isolamento & purificação , Infecções por Orthomyxoviridae/imunologia , Orthomyxoviridae/patogenicidade , Probióticos/administração & dosagem , Animais , Peso Corporal , Células Cultivadas , Modelos Animais de Doenças , Lactobacillus plantarum/imunologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/microbiologia , Pulmão/virologia , Camundongos , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/terapiaRESUMO
Introduction: The aim of this work was to characterize a new strain of Ligilactobacillus salivarius (CNCM I-4866) (CNCM I-4866) to address its potential as probiotic with a special focus on intestinal inflammation. Potential anti-inflammatory abilities of this strain were evaluated through in vivo and in vitro experiments. Methods: Firstly, the strain was tested in a murine acute inflammation colitis model induced by DNBS. In vitro characterization was then performed with diverse tests: modulation capability of intestinal permeability; study of the impact on immunity profile through cytokines dosage; capacity to inhibit pathogens and adhere to intestinal cells lines. Production of metabolites, antibiotic resistance and survival to gastro-intestinal tract conditions were also tested. Results: In vitro assay has shown a reduction of colonic damage and markers of inflammation after treatment with CNCM I-4866. Transcriptomic analysis performed on colons showed the capacity of the strain to down-regulate pro-inflammatory cytokines. L. salivarius CNCM I-4866 exerted anti-inflammatory profile by reducing IL-8 production by TNF-α stimulated cell and modulated cytokines profile on peripheral blood mononuclear cells (PBMC). It protected intestinal integrity by increasing trans-epithelial electrical resistance (TEER) on Caco-2 TNF-α inflamed cells. Additionally, L. salivarius CNCM I-4866 displayed inhibition capacity on several intestinal pathogens and adhered to eukaryotic cells. Regarding safety and technical concerns, CNCM I-4866 was highly resistant to 0.3% of bile salts and produced mainly L-lactate. Finally, strain genomic characterization allowed us to confirm safety aspect of our strain, with no antibiotic gene resistance found. Discussion: Taken together, these results indicate that L. salivarius CNCM I-4866 could be a good probiotic candidate for intestinal inflammation, especially with its steady anti-inflammatory profile.
RESUMO
Microbiota studies have dramatically increased over these last two decades, and the repertoire of microorganisms with potential health benefits has been considerably enlarged. The development of next generation probiotics from new bacterial candidates is a long-term strategy that may be more efficient and rapid with discriminative in vitro tests. Streptococcus strains have received attention regarding their antimicrobial potential against pathogens of the upper and, more recently, the lower respiratory tracts. Pathogenic bacterial strains, such as non-typable Haemophilus influenzae (NTHi), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus), are commonly associated with acute and chronic respiratory diseases, and it could be interesting to fight against pathogens with probiotics. In this study, we show that a Streptococcus mitis (S. mitis) EM-371 strain, isolated from the buccal cavity of a human newborn and previously selected for promising anti-inflammatory effects, displayed in vitro antimicrobial activity against NTHi, P. aeruginosa or S. aureus. However, the anti-pathogenic in vitro activity was not sufficient to predict an efficient protective effect in a preclinical model. Two weeks of treatment with S. mitis EM-371 did not protect against, and even exacerbated, NTHi lung infection.
Assuntos
Pneumonia , Infecções Respiratórias , Infecções Estafilocócicas , Recém-Nascido , Humanos , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/microbiologia , Staphylococcus aureus , Streptococcus mitis , Bactérias , Haemophilus influenzae , Antibacterianos/farmacologia , PulmãoRESUMO
Experimental and clinical evidence has demonstrated the potential of probiotic strains in the prevention or treatment of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). However, there is little data on what the methodology leading to the identification of such strains should be. In this work, we propose a new flowchart to identify strains with probiotic potential for the management of IBS and IBD, which we tested on a collection of 39 lactic acid bacteria and Bifidobacteria strains. This flowchart included in vitro tests of immunomodulatory properties on intestinal and peripheral blood mononuclear cells (PBMCs), assessment of the barrier-strengthening effect by measuring transepithelial electric resistance (TEER) and quantification of short-chain fatty acids (SCFAs) and aryl hydrocarbon receptor (AhR) agonists produced by the strains. The in vitro results were then combined in a principal component analysis (PCA) to identify strains associated with an anti-inflammatory profile. To validate our flowchart, we tested the two most promising strains identified in the PCA in mouse models of post-infectious IBS or chemically induced colitis to mimic IBD. Our results show that this screening strategy allows the identification of strains with potential beneficial effects on colonic inflammation and colonic hypersensitivity.
RESUMO
With its antimicrobial and immunomodulating properties, the cathelicidin (LL37) plays an important role in innate immune system. Here, we attempted to alleviate chemically induced colitis using a lactococci strain that either directly expressed the precursor to LL37, hCAP18 (LL-pSEC:hCAP18), or delivered hCAP18 cDNA to host cells under the control of the cytomegalovirus promoter (LL-Probi-H1:hCAP18). We also investigated whether the alleviation of symptoms could be explained through modification of the gut microbiota by hCAP18. Mice were administered daily doses of LL-pSEC:hCAP18 or LL-Probi-H1:hCAP18. On day 7, colitis was induced by DNBS. During autopsy, we assessed macroscopic tissue damage in the colon and collected tissue samples for the characterization of inflammation markers and histological analysis. Feces were collected at day 7 for 16S DNA sequencing. We also performed a fecal transplant experiment in which mice underwent colon washing and received feces from Lactococcus lactis-treated mice before DNBS-colitis induction. Treatment with LL-Probi-H1:hCAP18 reduced the severity of colitis symptoms. The protective effects were accompanied by increased levels of IL17A and IL10 in mesenteric lymph node cells. L. lactis administration altered the abundance of Lachnospiraceae and Muribaculaceae. However, fecal transplant from L. lactis-treated mice did not improve DNBS-induced symptoms in recipient mice.
Assuntos
Catelicidinas/metabolismo , Colite , Lactococcus lactis , Animais , Colite/induzido quimicamente , Colite/genética , Colite/terapia , Citocinas/metabolismo , DNA Complementar/metabolismo , Dinitrofluorbenzeno/análogos & derivados , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-17/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Christensenellaceae is a family of subdominant commensal bacteria found in humans. It is thought to play an important role in gut health by maintaining microbial symbiosis. Indeed, these bacteria occur at significantly lower levels or are absent in individuals suffering from inflammatory bowel diseases (IBDs). Here, we explored if type species Christensenella minuta (strain: DSM 22607) could have the potential to help treat IBDs. We assessed key properties displayed by the bacterium using a combination of in vitro and in vivo assays. We found that while C. minuta is a strict anaerobe, it is also oxygen tolerant. Additionally, we observed that the species produces high levels of acetate and moderate levels of butyrate. We performed deep phenotyping using Biolog microarrays. Using human intestinal cell lines, we discovered that C. minuta demonstrated strong anti-inflammatory activity, resulting in reduced levels of proinflammatory IL-8 cytokines via the inhibition of the NF-κB signaling pathway. Furthermore, C. minuta protected intestinal epithelial integrity in vitro. Finally, in two distinct animal models of acute colitis, C. minuta prevented intestinal damage, reduced colonic inflammation, and promoted mucosal healing. Together, these results indicate that C. minuta has potent immunomodulatory properties, underscoring its potential use in innovative microbiome-based IBD biotherapies.
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Anti-Inflamatórios/farmacologia , Clostridiales , Colite , Mucosa Intestinal , Animais , Células CACO-2 , Colite/induzido quimicamente , Colite/metabolismo , Colite/terapia , Modelos Animais de Doenças , Células HT29 , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Masculino , CamundongosRESUMO
Consumption of dairy products is one of the most natural ways to introduce probiotics. However, the beneficial effects of the probiotics might depend on the administration form. The aim of this study was to investigate the beneficial properties of two probiotic strains: Bifidobacterium animalis subsp. lactis (BB-12) and Lactobacillus acidophilus (LA-5) in different administration forms (capsules and yogurt). First, in vitro resistance to gastrointestinal condition, surface properties, and immunomodulation capacities were determined. Then, the anti-inflammatory properties of the probiotic strains administrated on yogurt or capsules were tested in a dinitrobenzene sulfonic acid (DNBS)-induced colitis mouse model. The survival rates of BB-12 and LA-5 strains to gastrointestinal conditions were slightly higher when yogurt was used as carrier. They showed most affinity to hexane (no-polar basic solvent) than ethyl-acetate (polar basic solvent). BB-12 showed the higher binding capacity to HT-29, Caco-2, and mucin. Both probiotic candidates suppress the secretion of IL-8 secretion by HT-29-TNF-α stimulated cells. Finally, administration of BB-12 and LA-5 strains improve colitis in mice. They protect against weight loss, inflammation, and hyperpermeability induced by DNBS. However, these anti-inflammatory effects were limited when mice were treated with the probiotic strain on a yogurt matrix. Overall results indicate that BB-12 and LA-5 positive properties are compromised depending on the matrix. Consequently, the selection of an appropriate matrix is an important criterion to conserve the positive benefits of these probiotic strains.
Assuntos
Bifidobacterium animalis , Colite , Lactobacillus acidophilus , Probióticos , Animais , Células CACO-2 , Cápsulas , Colite/induzido quimicamente , Colite/terapia , Células HT29 , Humanos , Camundongos , Probióticos/administração & dosagem , IogurteRESUMO
The yeast-like epiphytic fungus Pseudozyma flocculosa is known to antagonize powdery mildew fungi through proliferation on colonies presumably preceded by the release of an antifungal glycolipid (flocculosin). In culture conditions, P. flocculosa can be induced to produce or not flocculosin through manipulation of the culture medium nutrients. In order to characterize and understand the metabolic changes in P. flocculosa linked to glycolipid production, we conducted a 2-DE proteomic analysis and compared the proteomic profile of P. flocculosa growing under conditions favoring the development of the fungus (control) or conducive to flocculosin synthesis (stress). A large number of protein spots (771) were detected in protein extracts of the control treatment compared to only 435 matched protein spots in extracts of the stress cultures, which clearly suggests an important metabolic reorganization in slow-growing cells producing flocculosin. From the latter treatment, we were able to identify 21 protein spots that were either specific to the treatment or up-regulated significantly (2-fold increase). All of them were identified based on similarity between predicted ORF of the newly sequenced genome of P. flocculosa with Ustilago maydis' available annotated sequences. These proteins were associated with the carbon and fatty acid metabolism, and also with the filamentous change of the fungus leading to flocculosin production. This first look into the proteome of P. flocculosa suggests that flocculosin synthesis is elicited in response to specific stress or limiting conditions.
RESUMO
Bacteroides thetaiotaomicron is one of the most abundant gut symbiont species, whose contribution to host health through its ability to degrade dietary polysaccharides and mature the immune system is under intense scrutiny. In contrast, adhesion and biofilm formation, which are potentially involved in gut colonization and microbiota structure and stability, have hardly been investigated in this intestinal bacterium. To uncover B. thetaiotaomicron biofilm-related functions, we performed a transposon mutagenesis in the poorly biofilm-forming reference strain VPI-5482 and showed that capsule 4, one of the eight B. thetaiotaomicron capsules, hinders biofilm formation. We then showed that the production of capsules 1, 2, 3, 5, and 6 also inhibits biofilm formation and that decreased capsulation of the population correlated with increased biofilm formation, suggesting that capsules could be masking adhesive surface structures. In contrast, we showed that capsule 8 displayed intrinsic adhesive properties. Finally, we demonstrated that BT2934, the wzx homolog of the B. thetaiotaomicron glycosylation locus, competes with capsule production and impacts its adhesion capacity. This study therefore establishes B. thetaiotaomicron capsule regulation as a major determinant of B. thetaiotaomicron biofilm formation, providing new insights into how modulation of different B. thetaiotaomicron surface structures affects in vitro biofilm formation.IMPORTANCE The human gut harbors a complex bacterial community that plays important roles in host health and disease, including nutrient acquisition, maturation of the immune system, and resistance to infections. The capacity to adhere to surfaces and form communities called biofilms is believed to be important for niche colonization and maintenance of gut bacteria. However, little is known about the adhesion capacity of most gut bacteria. In this study, we investigated biofilm formation in Bacteroides thetaiotaomicron, one of the most abundant bacteria of the normal mammalian intestine. We identified that B. thetaiotaomicron capsules, a group of eight surface-exposed polysaccharidic layers mediating important interactions with the gut environment, are also major determinants of biofilm formation that mask or unmask adhesion factors. Studying how B. thetaiotaomicron regulates its adhesion properties will allow us to better understand the physiology and specific properties of this important gut symbiont within anaerobic biofilms.
Assuntos
Cápsulas Bacterianas/genética , Bacteroides thetaiotaomicron/genética , Bacteroides thetaiotaomicron/fisiologia , Biofilmes/crescimento & desenvolvimento , Polissacarídeos Bacterianos/química , Animais , Aderência Bacteriana/genética , Cápsulas Bacterianas/química , Regulação Bacteriana da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C3H , Mutagênese , Organismos Livres de Patógenos EspecíficosRESUMO
The commensal bacterium Faecalibacterium prausnitzii plays a key role in inflammatory bowel disease (IBD) pathogenesis and serves as a general health biomarker in humans. However, the host molecular mechanisms that underlie its anti-inflammatory effects remain unknown. In this study we performed a transcriptomic approach on human intestinal epithelial cells (HT-29) stimulated with TNF-α and exposed to F. prausnitzii culture supernatant (SN) in order to determine the impact of this commensal bacterium on intestinal epithelial cells. Moreover, modulation of the most upregulated gene after F. prausnitzii SN contact was validated both in vitro and in vivo. Our results showed that F. prausnitzii SN upregulates the expression of Dact3, a gene linked to the Wnt/JNK pathway. Interestingly, when we silenced Dact3 expression, the effect of F. prausnitzii SN was lost. Butyrate was identified as the F. prausnitzii effector responsible for Dact3 modulation. Dact3 upregulation was also validated in vivo in both healthy and inflamed mice treated with either F. prausnitzii SN or the live bacteria, respectively. Finally, we demonstrated by colon transcriptomics that gut microbiota directly influences Dact3 expression. This study provides new clues about the host molecular mechanisms involved in the anti-inflammatory effects of the beneficial commensal bacterium F. prausnitzii.