RESUMO
BACKGROUND: The etiology of inflammatory bowel disease (IBD) is unclear but involves both genetics and environmental factors, including the gut microbiota. Indeed, exacerbated activation of the gastrointestinal immune system toward the gut microbiota occurs in genetically susceptible hosts and under the influence of the environment. For instance, a majority of IBD susceptibility loci lie within genes involved in immune responses, such as caspase recruitment domain member 9 (Card9). However, the relative impacts of genotype versus microbiota on colitis susceptibility in the context of CARD9 deficiency remain unknown. RESULTS: Card9 gene directly contributes to recovery from dextran sodium sulfate (DSS)-induced colitis by inducing the colonic expression of the cytokine IL-22 and the antimicrobial peptides Reg3ß and Reg3γ independently of the microbiota. On the other hand, Card9 is required for regulating the microbiota capacity to produce AhR ligands, which leads to the production of IL-22 in the colon, promoting recovery after colitis. In addition, cross-fostering experiments showed that 5 weeks after weaning, the microbiota transmitted from the nursing mother before weaning had a stronger impact on the tryptophan metabolism of the pups than the pups' own genotype. CONCLUSIONS: These results show the role of CARD9 and its effector IL-22 in mediating recovery from DSS-induced colitis in both microbiota-independent and microbiota-dependent manners. Card9 genotype modulates the microbiota metabolic capacity to produce AhR ligands, but this effect can be overridden by the implantation of a WT or "healthy" microbiota before weaning. It highlights the importance of the weaning reaction occurring between the immune system and microbiota for host metabolism and immune functions throughout life. A better understanding of the impact of genetics on microbiota metabolism is key to developing efficient therapeutic strategies for patients suffering from complex inflammatory disorders. Video Abstract.
Assuntos
Proteínas Adaptadoras de Sinalização CARD , Colite , Sulfato de Dextrana , Microbioma Gastrointestinal , Interleucina 22 , Interleucinas , Proteínas Associadas a Pancreatite , Animais , Proteínas Adaptadoras de Sinalização CARD/genética , Colite/microbiologia , Colite/genética , Colite/imunologia , Camundongos , Proteínas Associadas a Pancreatite/genética , Interleucinas/genética , Interleucinas/metabolismo , Camundongos Knockout , Predisposição Genética para Doença , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Colo/microbiologia , Colo/metabolismo , Doenças Inflamatórias Intestinais/microbiologia , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/imunologia , Feminino , MasculinoRESUMO
Oral administration of probiotics has been proposed as a promising biotherapy to prevent and treat different diseases related to gastrointestinal disorders, such as irritable bowel syndrome (IBS). Due to the increasing research area on the characterisation of new probiotic bacterial strains, it is necessary to perform suitable in vitro experiments, using pertinent cellular models, in order to establish appropriate readout profiles based on IBS symptoms and subtypes. In this work, a collection of 30 candidate strains, belonging mainly to the Lactobacillus and Bifidobacterium genera, were screened using three different sets of in vitro experiments with different readouts to identify promising probiotic strains with: (1) the ability to inhibit the synthesis of IL-8 production by TNF-α stimulated HT-29 cells, (2) immunomodulatory properties quantified as increased IL-10 levels in peripheral blood mononuclear cell (PBMCs), and (3) the ability to maintain epithelial barrier integrity by increasing the trans-epithelial/endothelial electrical resistance (TEER) values in Caco-2 cells. Based on these criteria, three strains were selected: Lactobacillus gasseri PI41, Lacticaseibacillus rhamnosus PI48 and Bifidobacterium animalis subsp. lactis PI50, and tested in a murine model of low-grade inflammation induced by dinitrobenzene sulfonic acid (DNBS), which mimics some of the symptoms of IBS. Among the three strains, L. gasseri PI41 improved overall host well-being by preventing body weight loss in DNBS-treated mice and restored gut homeostasis by normalising the intestinal permeability and reducing pro-inflammatory markers. Therefore, the potential of this strain was confirmed in a second murine model known to reproduce IBS symptoms: the neonatal maternal separation (NMS) model. The PI41 strain was effective in preventing intestinal permeability and reducing colonic hypersensitivity. In conclusion, the set of in vitro experiments combined with in vivo assessments allowed us to identify a promising probiotic candidate strain, L. gasseri PI41, in the context of IBS.
Assuntos
Síndrome do Intestino Irritável , Probióticos , Probióticos/administração & dosagem , Probióticos/farmacologia , Síndrome do Intestino Irritável/terapia , Síndrome do Intestino Irritável/microbiologia , Humanos , Animais , Camundongos , Células CACO-2 , Células HT29 , Modelos Animais de Doenças , Leucócitos Mononucleares/imunologia , Lactobacillus/fisiologia , Interleucina-8/metabolismo , Bifidobacterium/fisiologia , Interleucina-10 , Lactobacillus gasseri , Lacticaseibacillus rhamnosus/fisiologia , Masculino , Bifidobacterium animalis/fisiologiaRESUMO
BACKGROUND: Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. RESULTS: The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota. CONCLUSIONS: Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.
Assuntos
Colite , Microbioma Gastrointestinal , Microbiota , Camundongos , Animais , Microbioma Gastrointestinal/fisiologia , Modelos Animais de Doenças , Inflamação , Colite/induzido quimicamente , MamíferosRESUMO
Most lactobacilli produce extracellular polysaccharides that are considered to contribute to the probiotic effect of many strains. Lacticaseibacillus rhamnosus CNCM I-3690 is an anti-inflammatory strain able to counterbalance gut barrier dysfunction. In this study ten spontaneous variants of CNCM I-3690 with different EPS-production were generated and characterized by their ropy phenotype, the quantification of the secreted EPS and genetic analysis. Amongst them, two were further analysed in vitro and in vivo: an EPS over-producer (7292) and a low-producer derivative of 7292 (7358, with similar EPS levels than the wild type (WT) strain). Our results showed that 7292 does not have anti-inflammatory profile in vitro, and lost the capacity to adhere to the colonic epithelial cells as well as the protective effect on the permeability. Finally, 7292 lost the protective effects of the WT strain in a murine model of gut dysfunction. Notably, strain 7292 was unable to stimulate goblet cell mucus production and colonic IL-10 production, all key features for the beneficial effect of the WT strain. Furthermore, transcriptome analysis of colonic samples from 7292-treated mice showed a down-regulation of anti-inflammatory genes. Altogether, our results point out that the increase of EPS production in CNCM I-3690 impairs its protective effects and highlight the importance of the correct EPS synthesis for the beneficial effects of this strain.
Assuntos
Lacticaseibacillus rhamnosus , Probióticos , Animais , Camundongos , Lacticaseibacillus , Lactobacillus , Células Caliciformes , Anti-Inflamatórios , Polissacarídeos Bacterianos/farmacologiaRESUMO
Gut dysbiosis has been strongly correlated with colorectal cancer (CRC) development and the use of probiotics to modulate this imbalance represents a potential and promising therapy to prevent and treat CRC. For this reason, the identification of novel probiotic strains from diverse origins has widely increased in recent years, including traditional fermented foods. In this work we describe a new strain previously isolated from pulque (a traditional Mexican beverage), Levilactobacillus brevis CNCM I-5321, which may represent an interesting probiotic candidate to prevent and treat cancer. Indeed, our results show that CNCM I-5321 displays significant and specific antiproliferative capacities in human intestinal cancer cell lines (HT-29, HTC-116 and Caco-2 cells), but not in normal cells (FH cells). In addition, CNCM I-5321 is able to induce: (1) a pro-inflammatory immune response through stimulation of interleukin (IL)-2, IL-6, IL-12 and IL-17 cytokines and (2) apoptosis via activation of caspase 8. On the other hand, a minimum inhibitory concentration (MIC) assay revealed phenotypic resistance of this strain to ampicillin and chloramphenicol. However, no known transferable determinants were found in the genome of CNCM I-5321, thus this probiotic candidate presents no risk of horizontal transfer to the intestinal bacterial population. Finally, the safety status of CNCM I-5321 was evaluated using an innovative model of chicken embryo chorioallantoic membrane (CAM) to assess undesirable and/or toxic effects. Overall, our results support that CNCM I-5321 strain is non-pathogenic and safe for potential use as an anti-cancer candidate in human and animal medicine.
Assuntos
Apoptose , Proliferação de Células , Levilactobacillus brevis , Probióticos , Probióticos/farmacologia , Humanos , Levilactobacillus brevis/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Células CACO-2 , Citocinas/metabolismo , Testes de Sensibilidade Microbiana , Embrião de Galinha , Células HT29 , Galinhas/microbiologia , Neoplasias Colorretais/tratamento farmacológico , Células HCT116 , Linhagem Celular TumoralRESUMO
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.
Assuntos
Ácidos Graxos Ômega-3 , Efeitos Tardios da Exposição Pré-Natal , Animais , Comportamento Animal , Encéfalo , Feminino , Humanos , Inflamação , Microglia , GravidezRESUMO
Beneficial bacteria represent potential sources of therapy, particularly in the battle against antibiotic-resistant pathogens. The Gram-negative bacillus Klebsiella pneumoniae is not only a paradigm of multi-resistant opportunistic pathogen, but it is also able to colonise the human intestine and displays a high capacity to form biofilm. In this study, the anti-biofilm activity of 140 neutralised Lactobacillus supernatants was assessed against K. pneumoniae. Among the 13 strains whose supernatant significantly impaired biofilm formation, Lactobacillus plantarum CIRM653 was selected because it was also able to impair K. pneumoniae preformed biofilm, independently of a bactericidal effect. Mixed K. pneumoniae/L. plantarum CIRM653 biofilms had reduced tridimensional structures associated with a significant decrease in K. pneumoniae biomass. Further investigation showed that L. plantarum CIRM653 supernatant induced transcriptional modifications of K. pneumoniae biofilm-related genes, including down-regulation of the quorum sensing-related lsr operons and over-expression of type 3 pili structure genes. Increased production of type 3 pili was validated by Western-blot, hemagglutination and adhesion assays. L. plantarum CIRM653 activity against K. pneumoniae was also assessed in a murine intestinal colonisation model: a constant faecal pathogen burden was observed, as against a gradual decrease in the control group. These results reveal that an in vitro a priori attracting anti-biofilm activity of Lactobacillus might be counterbalanced by an in vivo behaviour in a complex microbiota environment with potential deleterious dispersal of highly adherent K. pneumoniae cells, raising the question of the accuracy of in vitro assays in screening of beneficial microbes.
Assuntos
Antibiose , Biofilmes/crescimento & desenvolvimento , Trato Gastrointestinal/microbiologia , Klebsiella pneumoniae/crescimento & desenvolvimento , Lactobacillus plantarum/fisiologia , Animais , Aderência Bacteriana/genética , Proteínas de Bactérias/genética , Técnicas de Cocultura , Fímbrias Bacterianas/genética , Klebsiella pneumoniae/genética , Lactobacillus/classificação , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/fisiologia , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Camundongos , Percepção de Quorum/genética , Transcrição GênicaRESUMO
Microbiota-modulating strategies, including probiotic administration, have been tested for the treatment of chronic gastrointestinal diseases despite limited information regarding their mechanisms of action. We previously demonstrated that patients with active celiac disease have decreased duodenal expression of elafin, a human serine protease inhibitor, and supplementation of elafin by a recombinant Lactococcus lactis strain prevents gliadin-induced immunopathology in the NOD/DQ8 mouse model of gluten sensitivity. The commensal probiotic strain Bifidobacterium longum NCC2705 produces a serine protease inhibitor (Srp) that exhibits immune-modulating properties. Here, we demonstrate that B. longum NCC2705, but not a srp knockout mutant, attenuates gliadin-induced immunopathology and impacts intestinal microbial composition in NOD/DQ8 mice. Our results highlight the beneficial effects of a serine protease inhibitor produced by commensal B. longum strains.IMPORTANCE Probiotic therapies have been widely used to treat gastrointestinal disorders with variable success and poor mechanistic insight. Delivery of specific anti-inflammatory molecules has been limited to the use of genetically modified organisms, which has raised some public and regulatory concerns. By examining a specific microbial product naturally expressed by a commensal bacterial strain, we provide insight into a mechanistic basis for the use of B. longum NCC2705 to help treat gluten-related disorders.
RESUMO
Lactic acid bacteria (LAB) are promising vectors of choice to deliver active molecules to mucosal tissues. They are recognized as safe by the World Health Organization and some strains have probiotic properties. The wide range of potential applications of LAB-driven mucosal delivery includes control of inflammatory bowel disease, vaccine delivery, and management of auto-immune diseases. Because of this potential, strategies for the display of proteins at the surface of LAB are gaining interest. To display a protein at the surface of LAB, a signal peptide and an anchor domain are necessary. The recombinant protein can be attached to the membrane layer, using a transmembrane anchor or a lipoprotein-anchor, or to the cell wall, by a covalent link using sortase mediated anchoring via the LPXTG motif, or by non-covalent liaisons employing binding domains such as LysM or WxL. Both the stability and functionality of the displayed proteins will be affected by the kind of anchor used. The most commonly surfaced exposed recombinant proteins produced in LAB are antigens and antibodies and the most commonly used LAB are lactococci and lactobacilli. Although it is not necessarily so that surface-display is the preferred localization in all cases, it has been shown that for certain applications, such as delivery of the human papillomavirus E7 antigen, surface-display elicits better biological responses, compared to cytosolic expression or secretion. Recent developments include the display of peptides and proteins targeting host cell receptors, for the purpose of enhancing the interactions between LAB and host. Surface-display technologies have other potential applications, such as degradation of biomass, which is of importance for some potential industrial applications of LAB.
Assuntos
Antígenos de Superfície/metabolismo , Biotecnologia/métodos , Biotecnologia/tendências , Lactobacillus/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Proteínas de Transporte/metabolismo , Humanos , Ácido Láctico/metabolismoRESUMO
Visceral pain and intestinal dysbiosis are associated with Irritable Bowel Syndrome (IBS), a common functional gastrointestinal disorder without available efficient therapies. In this study, a decrease of Faecalibacterium prausnitzii presence has been observed in an IBS-like rodent model induced by a neonatal maternal separation (NMS) stress. Moreover, it was investigated whether F. prausnitzii may have an impact on colonic sensitivity. The A2-165 reference strain, but not its supernatant, significantly decreased colonic hypersensitivity induced by either NMS in mice or partial restraint stress in rats. This effect was associated with a reinforcement of intestinal epithelial barrier. Thus, F. prausnitzii exhibits anti-nociceptive properties, indicating its potential to treat abdominal pain in IBS patients.
Assuntos
Faecalibacterium prausnitzii/fisiologia , Mucosa Intestinal , Síndrome do Intestino Irritável/etiologia , Animais , Colo/imunologia , Colo/metabolismo , Colo/microbiologia , Modelos Animais de Doenças , Síndrome do Intestino Irritável/metabolismo , Síndrome do Intestino Irritável/microbiologia , Masculino , Privação Materna , Camundongos , Permeabilidade , Estresse FisiológicoRESUMO
BACKGROUND: Crohn's disease (CD)-associated dysbiosis is characterised by a loss of Faecalibacterium prausnitzii, whose culture supernatant exerts an anti-inflammatory effect both in vitro and in vivo. However, the chemical nature of the anti-inflammatory compounds has not yet been determined. METHODS: Peptidomic analysis using mass spectrometry was applied to F. prausnitzii supernatant. Anti-inflammatory effects of identified peptides were tested in vitro directly on intestinal epithelial cell lines and on cell lines transfected with a plasmid construction coding for the candidate protein encompassing these peptides. In vivo, the cDNA of the candidate protein was delivered to the gut by recombinant lactic acid bacteria to prevent dinitrobenzene sulfonic acid (DNBS)-colitis in mice. RESULTS: The seven peptides, identified in the F. prausnitzii culture supernatants, derived from a single microbial anti-inflammatory molecule (MAM), a protein of 15â kDa, and comprising 53% of non-polar residues. This last feature prevented the direct characterisation of the putative anti-inflammatory activity of MAM-derived peptides. Transfection of MAM cDNA in epithelial cells led to a significant decrease in the activation of the nuclear factor (NF)-κB pathway with a dose-dependent effect. Finally, the use of a food-grade bacterium, Lactococcus lactis, delivering a plasmid encoding MAM was able to alleviate DNBS-induced colitis in mice. CONCLUSIONS: A 15â kDa protein with anti-inflammatory properties is produced by F. prausnitzii, a commensal bacterium involved in CD pathogenesis. This protein is able to inhibit the NF-κB pathway in intestinal epithelial cells and to prevent colitis in an animal model.
Assuntos
Proteínas de Bactérias/metabolismo , Clostridiales/metabolismo , Doença de Crohn/microbiologia , Disbiose/microbiologia , Mucosa Intestinal/microbiologia , Sequência de Aminoácidos , Animais , Anti-Inflamatórios/uso terapêutico , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/uso terapêutico , Biomarcadores/metabolismo , Linhagem Celular , Colite/induzido quimicamente , Colite/metabolismo , Colite/prevenção & controle , Doença de Crohn/metabolismo , Doença de Crohn/patologia , Disbiose/metabolismo , Disbiose/patologia , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , NF-kappa B/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Impaired gut barrier function has been reported in a wide range of diseases and syndromes and in some functional gastrointestinal disorders. In addition, there is increasing evidence that suggests the gut microbiota tightly regulates gut barrier function and recent studies demonstrate that probiotic bacteria can enhance barrier integrity. Here, we aimed to investigate the effects of Lactobacillus rhamnosus CNCM I-3690 on intestinal barrier function. In vitro results using a Caco-2 monolayer cells stimulated with TNF-α confirmed the anti-inflammatory nature of the strain CNCM I-3690 and pointed out a putative role for the protection of the epithelial function. Next, we tested the protective effects of L. rhamnosus CNCM I-3690 in a mouse model of increased colonic permeability. Most importantly, we compared its performance to that of the well-known beneficial human commensal bacterium Faecalibacterium prauznitzii A2-165. Increased colonic permeability was normalized by both strains to a similar degree. Modulation of apical tight junction proteins expression was then analyzed to decipher the mechanism underlying this effect. We showed that CNCM I-3690 partially restored the function of the intestinal barrier and increased the levels of tight junction proteins Occludin and E-cadherin. The results indicate L. rhamnosus CNCM I-3690 is as effective as the commensal anti-inflammatory bacterium F. prausnitzii to treat functional barrier abnormalities.
Assuntos
Anti-Inflamatórios/administração & dosagem , Clostridium/fisiologia , Mucosa Intestinal/fisiologia , Lacticaseibacillus rhamnosus/fisiologia , Permeabilidade/efeitos dos fármacos , Probióticos/administração & dosagem , Experimentação Animal , Animais , Células CACO-2 , Clostridium/crescimento & desenvolvimento , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/microbiologia , Perfilação da Expressão Gênica , Humanos , Mucosa Intestinal/efeitos dos fármacos , Lacticaseibacillus rhamnosus/crescimento & desenvolvimento , Masculino , Camundongos Endogâmicos C57BL , Proteínas de Junções Íntimas/biossíntese , Resultado do Tratamento , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The impact of gut microbiota in eliciting innate and adaptive immune responses beneficial for the host in the context of effective therapies against cancer has been highlighted recently. Chemotherapeutic agents, by compromising, to some extent, the intestinal integrity, increase the gut permeability and selective translocation of Gram-positive bacteria in secondary lymphoid organs. There, anticommensal pathogenic Th17 T-cell responses are primed, facilitating the accumulation of Th1 helper T cells in tumor beds after chemotherapy as well as tumor regression. Importantly, the redox equilibrium of myeloid cells contained in the tumor microenvironment is also influenced by the intestinal microbiota. Hence, the anticancer efficacy of alkylating agents (such as cyclophosphamide) and platinum salts (oxaliplatin, cis-platin) is compromised in germ-free mice or animals treated with antibiotics. These findings represent a paradigm shift in our understanding of the mode of action of many compounds having an impact on the host-microbe mutualism.
Assuntos
Antineoplásicos/farmacologia , Intestinos/microbiologia , Microbiota/imunologia , Neoplasias/imunologia , Neoplasias/microbiologia , Células Th17/imunologia , Animais , Antibacterianos/farmacologia , Humanos , Mucosa Intestinal/patologia , CamundongosRESUMO
The human gut houses one of the most complex and abundant ecosystems composed of up to 1013-1014 microorganisms. Although the anthropocentric concept of life has concealed the function of microorganisms inside us, the important role of gut bacterial community in human health is well recognised today. Moreover, different microorganims, which are commonly present in a large diversity of food products, transit through our gut every day adding in some cases a beneficial effect to our health (probiotics). This crosstalk is concentrated mainly in the intestinal epithelium, where microbes provide the host with essential nutrients and modulation of the immune system. Furthermore, microorganisms also display antimicrobial activities maintaining a gut ecosystem stable. This review summarises some of the recent findings on the interaction of both commensal and probiotic bacteria with each other and with the host. The aim is to highlight the cooperative status found in healthy individuals as well as the importance of this crosstalk in the maintenance of human homeostasis.
Assuntos
Mucosa Intestinal/microbiologia , Microbiota/imunologia , Simbiose , Peptídeos Catiônicos Antimicrobianos/biossíntese , Butiratos/metabolismo , Ecossistema , Alimentos , Humanos , Imunomodulação , Mucosa Intestinal/imunologia , Mucosa Intestinal/virologia , Fenômenos Fisiológicos da Nutrição , ProbióticosRESUMO
Probiotics have been proposed as a therapy for inflammatory bowel disease, but variations in strains, formulations, and protocols used in clinical trials have hindered the creation of guidelines for their use. Thus, preclinical insight into the mechanisms of specific probiotic strains and mode of administration would be useful to guide future clinical trial design. In this study, live, heat inactivated (HI), and spent culture medium preparations of the probiotic Bifidobacterium breve NCC2950 were administered to specific pathogen free C57BL/6 mice before or during colitis, as well as before colitis reactivation. Five days of 3.5% dextran sulphate sodium in drinking water was used to induce colitis. Pretreatment with live B. breve reduced disease severity, myeloperoxidase activity, microscopic damage, cytokine production, interleukin (IL)-12/IL-10 ratio, and lymphocyte infiltration in the colon. B. breve did not attenuate on-going colitis. After acute colitis, disease symptoms were normalised sooner with live and HI B. breve treatment; however, reactivation of colitis was not prevented. These findings indicate that the efficacy of a probiotic to modulate intestinal inflammation is dependent on the formulation as well as state of inflammation when administered. Overall, live B. breve was most efficacious in preventing acute colitis. Live and HI B. breve also promoted recovery from diarrhoea and colon bleeding after a bout of acute colitis.
Assuntos
Colite/microbiologia , Doenças Inflamatórias Intestinais/microbiologia , Probióticos/uso terapêutico , Animais , Bifidobacterium , Colite/induzido quimicamente , Colite/terapia , Sulfato de Dextrana , Diarreia/terapia , Doenças Inflamatórias Intestinais/induzido quimicamente , Doenças Inflamatórias Intestinais/terapia , Interleucina-10/sangue , Interleucina-12/sangue , Intestinos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peroxidase/metabolismo , Organismos Livres de Patógenos EspecíficosRESUMO
Faecalibacterium prausnitzii is the most abundant bacterium in the human intestinal microbiota of healthy adults, representing more than 5% of the total bacterial population. Over the past five years, an increasing number of studies have clearly described the importance of this highly metabolically active commensal bacterium as a component of the healthy human microbiota. Changes in the abundance of F. prausnitzii have been linked to dysbiosis in several human disorders. Administration of F. prausnitzii strain A2-165 and its culture supernatant have been shown to protect against 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in mice. Here, we discuss the role of F. prausnitzii in balancing immunity in the intestine and the mechanisms involved.
Assuntos
Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/fisiologia , Bactérias Gram-Positivas/imunologia , Bactérias Gram-Positivas/fisiologia , Simbiose , Animais , Humanos , CamundongosRESUMO
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.
Assuntos
Hipersensibilidade/terapia , Imunoterapia , Probióticos/uso terapêutico , Alérgenos/genética , Alérgenos/imunologia , Animais , Bifidobacterium/genética , DNA/administração & dosagem , Humanos , Hipersensibilidade/imunologia , Imunidade nas Mucosas , Lactobacillus/genética , Camundongos , Hipersensibilidade a Leite/terapia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/imunologiaRESUMO
Random insertional mutagenesis performed on a Lactococcus lactis reporter strain led us to identify L. lactis ybdD as a protein-overproducing mutant. In different expression contexts, the ybdD mutant shows increased levels of exported proteins and therefore constitutes a new and attractive heterologous protein production host. This study also highlights the importance of unknown regulatory processes that play a role during protein secretion.
Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Mutagênese InsercionalRESUMO
Rhodococcus equi causes severe pneumonia in foals and has recently gained attention as a significant opportunistic pathogen in immunocompromised humans. However, no effective vaccine to prevent rhodococcosis is currently available. In this study, we have engineered the food-grade bacterium Lactococcus lactis to secrete the virulence-associated protein A from R. equi (LL-VapA). The immunogenic potential of LL-VapA strain was then evaluated after either intragastric or intranasal immunization in mice either alone or in combination with LL-Lep, a recombinant strain of L. lactis secreting biologically active leptin, a pleiotropic hormone with significant immunomodulatory properties. Intragastric administration of LL-VapA led to the highest VapA-specific mucosal response whereas intranasal administration led to the highest systemic immune responses. Cytokines released from in vitro-stimulated spleen cells show both a strong IFN-γ response and an increase of IL-4 level in all immunized groups, except for the group intranasally co-administered with both LL-VapA and LL-Lep. Strikingly, a significant reduction in R. equi viable counts in liver and spleen was observed four days after intravenous challenge with a virulent strain of R. equi in all immunized groups except for the group vaccinated by intragastric route with LL-VapA. Altogether, our results demonstrate that LL-VapA can evoke a T(H)1-based protective immune response in intranasally immunized mice. This response is enhanced when co-administered with LL-Lep strain, whereas only co-administration of LL-VapA and LL-Lep can induce a protective immune response in intragastric vaccinated mice, associated with a T(H)1/T(H)2 cytokine response.