Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobio...Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization.Animals used as models of human diseases can be maintained in sterile conditions(isolators used for germ-free rearing)and specifically colonized with defined microbes(including non-cultivable commensal bacteria).The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models.Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia(i.e.,using models of human inflammatory bowel disease and colorectal carcinoma).In contrast,a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic(NOD)mice.Interestingly,the development of atherosclerosis in germ-free apolipoprotein E(ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals.Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota.Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial,disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components(e.g.,probiotics and prebiotics)whose administration may aid in disease prevention and treatment.展开更多
Increasing numbers of clinical trials and animal experiments have shown that probiotic bacteria are promising tools for allergy prevention. Here, we analyzed the immunomodulatory properties of three selected lactobaci...Increasing numbers of clinical trials and animal experiments have shown that probiotic bacteria are promising tools for allergy prevention. Here, we analyzed the immunomodulatory properties of three selected lactobacillus strains and the impact of their mixture on allergic sensitization to Bet v I using a gnotobiotic mouse model. We showed that Lactobacillus （L.） rhamnosus LOCK0900, L. rhamnosus LOCK0908 and L. casei LOCK0919 are recognized via Toll-like receptor 2 （TLR2） and nucleotide-binding oligomerization domain-containing protein 2 （NOD2） receptors and stimulate bone marrow-derived dendritic cells to produce cytokines in species- and strain-dependent manners. Colonization of germ-free （GF） mice with a mixture of all three strains （Lmix） improved the intestinal barrier by strengthening the apical junctional complexes of enterocytes and restoring the structures of microfilaments extending into the terminal web. Mice colonized with Lmix and sensitized to the Bet v I allergen showed significantly lower levels of allergen-specific IgE, IgG 1 and IgG2a and an elevated total IgA level in the sera and intestinal lavages as well as an increased transforming growth factor （TGF）-β level compared with the sensitized GF mice. Splenocytes and mesenteric lymph node cells from the Lmix-colonized mice showed the significant upregulation of TGF-β after in vitro stimulation with Bet v 1. Our results show that Lmix colonization improved the gut epithelial barrier and reduced allergic sensitization to Bet v 1. Furthermore, these findings were accompanied by the increased production of circulating and secretory IgA and the regulatory cytokine TGF-β. Thus, this mixture of three lactobacillus strains shows potential for use in the prevention of increased gut permeability and the onset of allergies in humans,展开更多
基金grants from the Czech Science Foundation(nos.303/08/0367,303/09/0449,310/07/014,305/08/0535,310/09/1640 and 310/08/H077)the Grant Agency of the Academy of Sciences of the Czech Republic(nos.IAA500200910,IAA500200710,KJB500200904,IAA500200917 and A500200709)+3 种基金the Ministry of Education,Youth and Sports of the Czech Republic(nos.2B06053,2B06155 and MSM 0021620812)the Ministry of Health of the Czech Republic(nos.NS/9775-4,NS/10054-3 and NS/10340-3)EU Project Marie Curie CT 215553,EU Project IPODD consortium(202020)the Institutional Research Concept AV0Z50200510.
文摘Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization.Animals used as models of human diseases can be maintained in sterile conditions(isolators used for germ-free rearing)and specifically colonized with defined microbes(including non-cultivable commensal bacteria).The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models.Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia(i.e.,using models of human inflammatory bowel disease and colorectal carcinoma).In contrast,a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic(NOD)mice.Interestingly,the development of atherosclerosis in germ-free apolipoprotein E(ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals.Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota.Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial,disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components(e.g.,probiotics and prebiotics)whose administration may aid in disease prevention and treatment.
基金The excellent technical assistance of J Jarkovska, A Smolova, I Grimova and D Drasnarova is gratefully acknowledged. This research was supported by grant NR12-0101-10/2011 of the Republic of Poland, grants P304/11/1252 and 303/09/0449 of the Czech Science Foundation, grants CZ.3.22/2.1.00/09.01574 and CZ.3.22/2.1.00/ 13.03892, grant SFB F46 from the Austrian Science Fund. and Institutional Research Concept RVO 61388971.
文摘Increasing numbers of clinical trials and animal experiments have shown that probiotic bacteria are promising tools for allergy prevention. Here, we analyzed the immunomodulatory properties of three selected lactobacillus strains and the impact of their mixture on allergic sensitization to Bet v I using a gnotobiotic mouse model. We showed that Lactobacillus （L.） rhamnosus LOCK0900, L. rhamnosus LOCK0908 and L. casei LOCK0919 are recognized via Toll-like receptor 2 （TLR2） and nucleotide-binding oligomerization domain-containing protein 2 （NOD2） receptors and stimulate bone marrow-derived dendritic cells to produce cytokines in species- and strain-dependent manners. Colonization of germ-free （GF） mice with a mixture of all three strains （Lmix） improved the intestinal barrier by strengthening the apical junctional complexes of enterocytes and restoring the structures of microfilaments extending into the terminal web. Mice colonized with Lmix and sensitized to the Bet v I allergen showed significantly lower levels of allergen-specific IgE, IgG 1 and IgG2a and an elevated total IgA level in the sera and intestinal lavages as well as an increased transforming growth factor （TGF）-β level compared with the sensitized GF mice. Splenocytes and mesenteric lymph node cells from the Lmix-colonized mice showed the significant upregulation of TGF-β after in vitro stimulation with Bet v 1. Our results show that Lmix colonization improved the gut epithelial barrier and reduced allergic sensitization to Bet v 1. Furthermore, these findings were accompanied by the increased production of circulating and secretory IgA and the regulatory cytokine TGF-β. Thus, this mixture of three lactobacillus strains shows potential for use in the prevention of increased gut permeability and the onset of allergies in humans,
