Project description:We implemented transcriptomic analyses of blood and hippocampus of old mice treated with Akkermansia muciniphila Membrane Protein for 8 weeks.
Project description:Total RNA from ileum of three groups of mice are sequenced. The three groups are 1. wild type mice. 2. mice with IFNg gene knockout. 3. IFNg gene knockout mice after colonization of Akkermansia muciniphila
Project description:Kees2018 - Genome-scale constraint-based
model of the mucin-degrader Akkermansia
muciniphila
This model is described in the article:
Model-driven design of a
minimal medium for Akkermansia muciniphila confirms mucus
adaptation.
van der Ark KCH, Aalvink S,
Suarez-Diez M, Schaap PJ, de Vos WM, Belzer C.
Microb Biotechnol 2018 Jan; :
Abstract:
The abundance of the human intestinal symbiont Akkermansia
muciniphila has found to be inversely correlated with several
diseases, including metabolic syndrome and obesity.
A. muciniphila is known to use mucin as sole carbon and
nitrogen source. To study the physiology and the potential for
therapeutic applications of this bacterium, we designed a
defined minimal medium. The composition of the medium was based
on the genome-scale metabolic model of A. muciniphila and
the composition of mucin. Our results indicate that
A. muciniphila does not code for GlmS, the enzyme that
mediates the conversion of fructose-6-phosphate (Fru6P) to
glucosamine-6-phosphate (GlcN6P), which is essential in
peptidoglycan formation. The only annotated enzyme that could
mediate this conversion is Amuc-NagB on locus Amuc_1822. We
found that Amuc-NagB was unable to form GlcN6P from Fru6P at
physiological conditions, while it efficiently catalyzed the
reverse reaction. To overcome this inability,
N-acetylglucosamine needs to be present in the medium for
A. muciniphila growth. With these findings, the
genome-scale metabolic model was updated and used to accurately
predict growth of A. muciniphila on synthetic media. The
finding that A. muciniphila has a necessity for GlcNAc,
which is present in mucin further prompts the adaptation to its
mucosal niche.
This model is hosted on
BioModels Database
and identified by:
MODEL1710040000.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Previous studies have implicated a causal role for the gut bacterium Akkermansia muciniphila in counteracting diet-induced obesity and metabolic dysfunctions. However, a systems level understanding of the molecular mechanisms underlying the anti-obesogenic effect of A. muciniphila is lacking. Using fructose-induced obese mice as a model, we carried out multiomics studies to investigate the molecular cascades mediating the effect of A. muciniphila. We found that A. muciniphila colonization in fructose-induced obese mice triggered significant shifts in gut microbiota composition as well as alterations in numerous gut and plasma metabolites and gene expression in the hypothalamus. Among these, we found that the metabolite oleoyl-ethanolamide in the gut and circulation and hypothalamic oxytocin are the key regulators of gut-brain interactions that underlie the A. muciniphila anti-obesity effect. Our multiomics investigation elucidates the molecular regulators and pathways involved in the communication between A. muciniphila in the gut and hypothalamic neurons that counter fructose-induced obesity .
Project description:Akkermansia muciniphila, a common member of the human gut microbiota, is considered to be a beneficial resident of the intestinal mucus layer. Surface-exposed molecules produced by this organism likely play important roles in colonization and communication with other microbes and the host, but the protein composition of the outer membrane has not been characterized thus far. Herein we identify A. muciniphila proteins after enrichment and fractionation of the outer membrane proteome of A. muciniphila.
Project description:This study was conducted in order to monitor whether or not Akkermansia muciniphila was able to grow and utilize human milk and human milk oligosaccharides by deploying its mucin degrading enzymes. Interestingly, A. muciniphila was able to grow in human milk producing Short Chain Fatty Acids and degrade milk oligosaccharides (2’-fucosyllactose, 3’-siallylactose) as well as lactose.
Project description:The anaerobic gut microbe Akkermansia muciniphila ATCC BAA-835 lives in the mucus layer where it is exposed to oxygen. To investigate how it survives the changing oxygen concentrations, we exposed a exponentially growing culture to oxygen. The experiment was performed in parallel fermentor systems. To one system we added 0.2l/h oxygen after the culture reached an OD of 0.1, while the other remained anaerobic. Samples were taken just before addition of oxygen, about 1h after and when the cell reached stationary phase.
Project description:Akkermansia muciniphila, a bacterium, is associated with good health, but data are lacking whether it confers health benefits on children in low income countries and by which mechanisms. In a case-control study of children <5 years old with (n=1717) or without (n=1524) diarrhea, the presence of A. muciniphila reduces the odds ratio of symptoms of diarrhea from six diarrheal pathogens. A. muciniphila is found more frequently among children who are growing well compared with those who are growing poorly. In silico analysis of 1487 A. muciniphila genomes revealed the presence of DNA encoding the peptide larazotide known to benefit human health by improving tight junctions. Although previously considered synthetic, we demonstrated that larazotide is secreted by A. muciniphila. Larazotide is found in the nucleus of colonic epithelial cells and its exogenous application alters gene expression. When larazotide is applied to colonic organoid cultures, the amount of mucin (MUC2) is increased significantly (p<0.005). Our analyses are consistent with A. muciniphila secreting larazotide and intestinal epithelial cells responding by increasing MUC2, potentially creating a positive feedback loop that increases mucin production, which may itself increase abundance of the mucin-metabolizing A. muciniphila. This cycle may confer positive health outcomes for children.
Project description:Akkermansia muciniphila, a mucin-degrading microbe found in the human gut, is often associated with positive health outcomes. The abundance of Akkermansia muciniphila is modulated by the presence and accessibility of nutrients, which can be derived from diet or host glycoproteins. In particular, the ability to degrade host mucins, a class of proteins carrying densely O-glycosylated domains, provides a competitive advantage in the sustained colonization of niche mucosal environments. Although Akkermansia muciniphila is known to rely on mucins as a carbon and nitrogen source, the enzymatic machinery used by this microbe to process mucins in the gut is not yet fully characterized. Here, we focus on the mucin-selective metalloprotease, Amuc_0627 (AM0627), which is known to cleave between adjacent residues carrying truncated core 1 O-glycans. We showed that this enzyme is capable of degrading purified mucin 2 (MUC2), the major protein component of mucus in the gut. An X-ray crystal structure of AM0627 (1.9 Å resolution) revealed O-glycan binding residues that are conserved between structurally characterized enzymes from the same family. We further rationalized the substrate cleavage motif using molecular modeling to identify nonconserved glycan-interacting residues. Mutagenesis of these residues resulted in altered substrate preferences down to the glycan level, providing insight into the structural determinants of O-glycan recognition.