Murein Lytic Enzyme TgaA of Bifidobacterium bifidum MIMBb75 Modulates Dendritic Cell Maturation through Its Cysteine- and Histidine-Dependent Amidohydrolase/Peptidase (CHAP) Amidase Domain

Guglielmetti, Simone; Zanoni, Ivan; Balzaretti, Silvia; Miriani, M.; Taverniti, Valentina; Noni, Ivano De; Presti, I.; Stuknytė, Milda; Scarafoni, Alessio; Arioli, Stefania; Iametti, Stefania; Bonomi, Francesco; Mora, Diego; Karp, Matti; Granucci, Francesca

doi:10.1128/aem.00761-14

Cited by 28 publications

(24 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Among the bifidobacteria that colonize the human infant gut, members of the Bifidobacterium bifidum species deserve a special mention (Turroni et al ., ), as they have been shown to metabolize host‐derived glycans, in particular human milk oligosaccharides (HMOs) (Turroni et al ., ; Sela, ) and mucin (Turroni et al ., 2010; 2011a; Gonzalez‐Rodriguez et al ., ). Recent studies performed under in vitro conditions as well as using an in vivo murine model highlighted the occurrence of various extracellular proteins produced by members of the species B. bifidum , such as sortase‐dependent pili or the murein lytic enzyme TgaA, both of which are presumed to be pivotal for their interaction with their host (Turroni et al ., 2013; 2014a; Guglielmetti et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Insights from genomes of representatives of the human gut commensal Bifidobacterium bifidum

Duranti

Milani

Lugli

et al. 2015

Environmental Microbiology

View full text Add to dashboard Cite

Summary Bifidobacteria are bacterial gut commensals of mammals, birds and social insects that are perceived to influence the metabolism/physiology of their host. In this context, members of the Bifidobacterium bifidum species are believed to significantly contribute to the overall microbiota of the human gut at infant stage. However, the molecular reasons for their adaptation to this environment are poorly understood. In this study, we analysed the pan‐genome of B. bifidum species by decoding genomes of 15 B. bifidum strains, which highlighted the existence of a conserved gene uniquely present in this bifidobacterial taxon, underscoring a nutrient acquisition strategy that targets host‐derived glycans, such as those present in mucin. Growth experiments and corresponding transcriptomic analyses confirmed the in silico data and supported these intriguing and unique host glycan‐specific saccharolytic features. The ubiquity of the genetic features of B. bifidum for the breakdown of host glycans was confirmed by interrogating metagenomic datasets, thereby supporting the notion that metabolic access to host‐derived glycans is a potent evolutionary force that has shaped B. bifidum genomes and consequently the ecology of the infant intestinal microbiota.

show abstract

Section: Introductionmentioning

confidence: 97%

Insights from genomes of representatives of the human gut commensal Bifidobacterium bifidum

Duranti

Milani

Lugli

et al. 2015

Environmental Microbiology

View full text Add to dashboard Cite

show abstract

“…One of the most studied mechanisms relates to the ability of probiotic bacteria to antagonize pathogenic organisms either by the excretion of antimicrobial agents (5) or by the displacement of pathogenic organisms through the competitive occupancy of adhesion sites (6). In addition, a number of reports suggest that health benefits result from stimulation of the immune system by components presented at the surfaces of probiotic strains (7,8). Both in vivo and in vitro experiments have demonstrated that the polysaccharides present at the surfaces of the bacteria, referred to either as capsule or as exopolysaccharides (EPSs), can play roles both in the displacement of pathogenic organisms and in the stimulation of the immune system (9,10).…”

mentioning

confidence: 99%

A Novel Rhamnose-Rich Hetero-exopolysaccharide Isolated from Lactobacillus paracasei DG Activates THP-1 Human Monocytic Cells

Balzaretti

Taverniti

Guglielmetti

et al. 2017

Appl Environ Microbiol

Self Cite

127

View full text Add to dashboard Cite

Lactobacillus paracasei DG is a bacterial strain with recognized probiotic properties and is used in commercial probiotic products. However, the mechanisms underlying its probiotic properties are mainly unknown. In this study, we tested the hypothesis that the ability of strain DG to interact with the host is at least partly associated with its ability to synthesize a surface-associated exopolysaccharide (EPS). Comparative genomics revealed the presence of putative EPS gene clusters in the DG genome; accordingly, EPS was isolated from the surface of the bacterium. A sample of the pure EPS from strain DG (DG-EPS), upon nuclear magnetic resonance (NMR) and chemical analyses, was shown to be a novel branched hetero-EPS with a repeat unit composed of L-rhamnose, D-galactose, and N-acetyl-D-galactosamine in a ratio of 4:1:1. Subsequently, we demonstrated that DG-EPS displays immunostimulating properties by enhancing the gene expression of the proinflammatory cytokines tumor necrosis factor alpha (TNF-␣) and interleukin 6 (IL-6), and particularly that of the chemokines IL-8 and CCL20, in the human monocytic cell line THP-1. In contrast, the expression of the cyclooxygenase enzyme COX-2 was not affected. In conclusion, DG-EPS is a bacterial macromolecule with the ability to boost the immune system either as a secreted molecule released from the bacterium or as a capsular envelope on the bacterial cell wall. This study provides additional information about the mechanisms supporting the cross talk between L. paracasei DG and the host. IMPORTANCEThe consumption of food products and supplements called probiotics (i.e., containing live microbial cells) to potentially prevent or treat specific diseases is constantly gaining popularity. The lack of knowledge on the precise mechanisms supporting their potential health-promoting properties, however, greatly limits a more appropriate use of each single probiotic strain. In this context, we studied a well-known probiotic, Lactobacillus paracasei DG, in order to identify the constitutive molecules that can explain the documented health-promoting properties of this bacterium. We found a novel polysaccharide molecule, named DG-EPS, that is secreted by and covers the bacterium. We demonstrated that this molecule, which has a chemical structure never identified before, has immunostimulatory properties and therefore may contribute to the ability of the probiotic L. paracasei DG to interact with the immune system. KEYWORDS

show abstract

“…The strain was selected as a representative of a species that has been reported to possess numerous host interaction properties (9), including marked adhesion to enterocytes (10)(11)(12), immunomodulation (12)(13)(14), and metabolism of mucin and human milk oligosaccharides (15,16).…”

mentioning

confidence: 99%

Consumption of a Bifidobacterium bifidum Strain for 4 Weeks Modulates Dominant Intestinal Bacterial Taxa and Fecal Butyrate in Healthy Adults

Gargari

Taverniti

Balzaretti

et al. 2016

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

Modulation of the intestinal microbial ecosystem (IME) is a useful target to establish probiotic efficacy in a healthy population. We conducted a randomized, double-blind, crossover, and placebo-controlled intervention study to determine the impact of Bifidobacterium bifidum strain Bb on the IME of adult healthy volunteers of both sexes. High-throughput 16S rRNA gene sequencing was used to characterize the fecal microbiota before and after 4 weeks of daily probiotic cell consumption. The intake of approximately one billion live B. bifidum cells affected the relative abundance of dominant taxa in the fecal microbiota and modulated fecal butyrate levels. Specifically, Prevotellaceae (P ‫؍‬ 0.041) and Prevotella (P ‫؍‬ 0.034) were significantly decreased, whereas Ruminococcaceae (P ‫؍‬ 0.039) and Rikenellaceae (P ‫؍‬ 0.010) were significantly increased. We also observed that the probiotic intervention modulated the fecal concentrations of butyrate in a manner dependent on the initial levels of short-chain fatty acids (SCFAs). In conclusion, our study demonstrates that a single daily administration of Bifidobacterium bifidum strain Bb can significantly modify the IME in healthy (not diseased) adults. These findings demonstrate the need to reassess the notion that probiotics do not influence the complex and stable IME of a healthy individual. IMPORTANCEFoods and supplements claimed to contain health-promoting probiotic microorganisms are everywhere these days and mainly intended for consumption by healthy people. However, it is still debated what actual effects probiotic products may have on the healthy population. In this study, we report the results of an intervention trial aimed at assessing the modifications induced in the intestinal microbial ecosystem of healthy adults from the consumption of a probiotic product. Our results demonstrate that the introduction of a probiotic product in the dietary habits of healthy people may significantly modify dominant taxa of the intestinal microbiota, resulting in the modulation of short-chain fatty acid concentrations in the gut. The overall changes witnessed in the probiotic intervention indicate a mechanism of microbiota modulation that could have potential effects on human health.

show abstract

Murein Lytic Enzyme TgaA of Bifidobacterium bifidum MIMBb75 Modulates Dendritic Cell Maturation through Its Cysteine- and Histidine-Dependent Amidohydrolase/Peptidase (CHAP) Amidase Domain

Cited by 28 publications

References 51 publications

Insights from genomes of representatives of the human gut commensal Bifidobacterium bifidum

Insights from genomes of representatives of the human gut commensal Bifidobacterium bifidum

A Novel Rhamnose-Rich Hetero-exopolysaccharide Isolated from Lactobacillus paracasei DG Activates THP-1 Human Monocytic Cells

Consumption of a Bifidobacterium bifidum Strain for 4 Weeks Modulates Dominant Intestinal Bacterial Taxa and Fecal Butyrate in Healthy Adults

Contact Info

Product

Resources

About