Three difficult-to-cultivate, strictly anaerobic strains, AN20
, AN421
, and AN502, were analyzed within a project studying possible probiotics for newly hatched chickens. Phylogenetic analyses ...showed that strains AN20
, AN421
, and AN502 formed two well-separated phylogenetic lineages in all phylogenetic and phylogenomic trees comprising members of the family
. Comparison to reference genomes of type species Bacteroides fragilis NCTC 9343
, Phocaeicola abscessus CCUG 55929
, and Capsularis zoogleoformans ATCC 33285
showed low relatedness based on the calculated genome-to-genome distance and orthologous average nucleotide identity. Analysis of fatty acid profiles showed iso-C
, anteiso-C
, C
, C
, and iso-C
3OH as the major fatty acids for all three strains and additionally C
3OH for AN421
and AN502. A specific combination of respiratory quinones different from related taxa was found in analyzed strains, MK-5 plus MK-11 in strain AN20
and MK-5 plus MK-10 in strains AN421
and AN502. Strains AN421
and AN502 harbor complete CRISPR loci with CRISPR array, type II-C, accompanied by a set of
genes (
,
, and
) in close proximity. Interestingly, strain AN20
was found to harbor two copies of
gene with >95% similarity to
of B. fragilis, suggesting a horizontal gene transfer between these taxa. In summary, three isolates characterized in this study represent two novel species, which we proposed to be classified in two novel genera of the family
, for which the names
sp. nov. (AN20
= CCM 9041
= DSM 111154
) and
sp. nov. (AN421
= CCM 9040
= DSM 111155
) are proposed.
This study represents follow-up research on three difficult-to-cultivate anaerobic isolates originally isolated within a project focused on strains that are able to stably colonize newly hatched chickens, thus representing possible probiotics. This project is exceptional in that it successfully isolates several miscellaneous strains that required modified and richly supplemented anaerobic media, as information on many gut-colonizing bacteria is based predominantly on metagenomic studies. Superior colonization of newly hatched chickens by
spp.,
spp., or related taxa can be considered of importance for development of future probiotics. Although different experiments can also be performed with provisionally characterized isolates, precise taxonomical definition is necessary for subsequent broad communication. The aim of this study is therefore to thoroughly characterize these isolates that represent novel genera and precisely determine their taxonomic position among related taxa to facilitate further research and communication involving these strains.
We derived mesenchymal stem cells (MSCs) from rat induced pluripotent stem cells (iPSCs) and transduced them with tumor necrosis factor alpha-stimulated gene-6 (TSG-6), to test whether TSG-6 ...overexpression would boost the therapeutic effects of iPSC-derived MSCs in experimental periodontitis.
A total of 30 female Sprague-Dawley (SD) rats were randomly divided into four groups: healthy control group (Group-N, n = 5), untreated periodontitis group (Group-P, n = 5), iPS-MSCs-treated and iPSC-MSCs/TSG-6-treated periodontitis groups (Group-P1 and P2, n = 10 per group). Experimental periodontitis was established by ligature and infection with Porphyromonas gingivalis around the maxillae first molar bilaterally. MSC-like cells were generated from rat iPSCs, and transducted with TSG-6. iPSC-MSCs or iPSC-MSCs/TSG-6 were administrated to rats in Group-P1 or P2 intravenously and topically, once a week for three weeks. Blood samples were obtained one week post-injection for the analysis of serum pro-inflammatory cytokines. All animals were killed 3 months post-treatment; maxillae were then dissected for histological analysis, tartrate-resistant acid phosphatase (TRAP) staining, and morphological analysis of alveolar bone loss.
Administration of iPSC-MSC/TSG-6 significantly decreased serum levels of IL-1β and TNF-α in the Group-P2 rats (65.78 pg/ml and 0.56 pg/ml) compared with those in Group-P (168.31 pg/ml and 1.15 pg/ml respectively) (p<0.05). Both alveolar bone loss and the number of TRAP-positive osteoclasts showed a significant decrease in rats that received iPSC-MSC/TSG-6 treatment compared to untreated rats in Group-P (p<0.05).
We demonstrated that overexpression of TSG-6 in rat iPSC-derived MSCs were capable of decreasing inflammation in experimental periodontitis and inhibiting alveolar bone resorption. This may potentially serve as an alternative stem-cell-based approach in the treatment and regeneration of periodontal tissues.
Bacteroides thetaiotaomicron (Bt) is a prominent member of the human gut microbiota with an extensive capacity for glycan harvest. This bacterium expresses a five-protein complex in the outer ...membrane, called the starch utilization system (Sus), which binds, degrades, and imports starch into the cell. Sus is a model system for the many glycan-targeting polysaccharide utilization loci found in Bt and other members of the Bacteroidetes phylum. Our previous work has shown that SusG, a lipidated amylase in the outer membrane, explores the entire cell surface but diffuses more slowly as it interacts with starch. Here, we use a combination of single-molecule tracking, super-resolution imaging, reverse genetics, and proteomics to show that SusE and SusF, two proteins that bind starch, are immobile on the cell surface even when other members of the system are knocked out and under multiple different growth conditions. This observation suggests a new paradigm for protein complex formation: binding proteins form immobile complexes that transiently associate with a mobile enzyme partner.
Aspiration pneumonia is a life-threatening infectious disease often caused by oral anaerobic and periodontal pathogens such as Porphyromonas gingivalis. This organism produces proteolytic enzymes, ...known as gingipains, which manipulate innate immune responses and promote chronic inflammation. Here, we challenged mice with P. gingivalis W83 and examined the role of gingipains in bronchopneumonia, lung abscess formation, and inflammatory responses. Although gingipains were not required for P. gingivalis colonization and survival in the lungs, they were essential for manifestation of clinical symptoms and infection-related mortality. Pathologies caused by wild-type (WT) P. gingivalis W83, including hemorrhage, necrosis, and neutrophil infiltration, were absent from lungs infected with gingipain-null isogenic strains or WT bacteria preincubated with gingipain-specific inhibitors. Damage to lung tissue correlated with systemic inflammatory responses, as manifested by elevated levels of TNF, IL-6, IL-17, and C-reactive protein. These effects were unequivocally dependent on gingipain activity. Gingipain activity was also implicated in the observed increase in IL-17 in lung tissues. Furthermore, gingipains increased platelet counts in the blood and activated platelets in the lungs. Arginine-specific gingipains made a greater contribution to P. gingivalis-related morbidity and mortality than lysine-specific gingipains. Thus, inhibition of gingipain may be a useful adjunct treatment for P. gingivalis-mediated aspiration pneumonia.
The periodontal pathogen Porphyromonas gingivalis is highly resistant to the bactericidal activity of human complement, which is present in the gingival crevicular fluid at 70% of serum ...concentration. All thirteen clinical and laboratory P. gingivalis strains tested were able to capture the human complement inhibitor C4b-binding protein (C4BP), which may contribute to their serum resistance. Accordingly, in serum deficient of C4BP, it was found that significantly more terminal complement component C9 was deposited on P. gingivalis. Moreover, using purified proteins and various isogenic mutants, we found that the cysteine protease high molecular weight arginine-gingipain A (HRgpA) is a crucial C4BP ligand on the bacterial surface. Binding of C4BP to P. gingivalis appears to be localized to two binding sites: on the complement control protein 1 domain and complement control protein 6 and 7 domains of the alpha-chains. Furthermore, the bacterial binding of C4BP was found to increase with time of culture and a particularly strong binding was observed for large aggregates of bacteria that formed during culture on solid blood agar medium. Taken together, gingipains appear to be a very significant virulence factor not only destroying complement due to proteolytic degradation as we have shown previously, but was also inhibiting complement activation due to their ability to bind the complement inhibitor C4BP.
Background and aims
The risk factors in the progression of nonalcoholic fatty liver disease (NAFLD) have not been fully clarified.
Porphyromonas gingivalis
(
P.g
) has been considered to be a ...confounding risk factor for systemic diseases. We aimed to evaluate the effect of
P.g
infection on risk of progression to NASH.
Methods
(1) Serum IgG antibody titers against
P.g
fimbriae (fimA) in 200 biopsy-proven NAFLD patients were measured by ELISA and compared with histological findings. (2) C57BL/6J mice were fed a control diet (CD) or high-fat diet (HFD) with or without
P.g
-odontogenic infection and analyzed histologically. Mouse livers were analyzed using CE–TOFMS and LC–TOFMS.
Results
(1) A significant correlation between fibrosis progression and antibody titers against
P.g
possessing fimA type 4 was identified (
P
= 0.0081). Multivariate analysis identified older age and type 4
P.g
-positivity as risk factors for advanced fibrosis. (2) Fibrosis and steatosis were more severe in HFD
P.g
(+) mice compared with HFD
P.g
(−) mice. In metabolome analysis, fatty acid metabolism was significantly disrupted with HFD in
P.g
-infected mouse livers. Monounsaturated/saturated fatty acid ratios were significantly higher in the HFD
P.g
(+) group than in the HFD
P.g
(−) group (
P
< 0.05). Moreover, expression levels of
SCD1
and
ELOVL6
were significantly reduced.
Conclusions
These results suggest that
P.g
infection is an important risk factor for pathological progression in NAFLD. Increase in the monounsaturated/saturated fatty acid ratio may be an important change that facilitates progression of NAFLD.
Objective
To investigate the possible link between Porphyromonas gingivalis infection and rheumatoid arthritis (RA), according to antibody profile, genetic and environmental factors, and RA severity.
...Methods
For assessing P gingivalis infection, serum levels of antibodies directed against P gingivalis lipopolysaccharide were measured in 694 patients with early RA who were not exposed to steroids or disease‐modifying antirheumatic drugs. Anti–P gingivalis antibody titers were compared between patients with early RA and various control groups, and according to various patient characteristics.
Results
Anti–P gingivalis antibody titers did not significantly differ between patients with RA and controls and did not significantly differ with anti–citrullinated protein antibody (ACPA), rheumatoid factor (RF), or HLA shared epitope status. Anti–P gingivalis antibody titers were significantly higher among patients who had never smoked compared to patients who had ever smoked (P = 0.0049). Among nonsmokers, high anti–P gingivalis antibody levels were associated with a higher prevalence of erosive change (47.5% versus 33.3% with modified Sharp/van der Heijde score erosion subscale ≥1; P = 0.0135).
Conclusion
In this large early RA cohort, we did not detect any association of anti–P gingivalis antibodies with RA or with ACPA status. These results suggest that the association of periodontitis and RA could be linked to bacterial species other than P gingivalis or to a mechanism other than citrullination. Nevertheless, we found higher anti–P gingivalis antibody titers in nonsmokers. In addition, in this population of nonsmokers, high anti–P gingivalis antibody titers were associated with more severe disease. We hypothesize that the role of tobacco in RA pathogenesis is so high that the effect of P gingivalis could be revealed only in a population not exposed to tobacco.
Within each bacterial species, different strains may vary in the set of genes they encode or in the copy number of these genes. Yet, taxonomic characterization of the human microbiota is often ...limited to the species level or to previously sequenced strains, and accordingly, the prevalence of intra-species variation, its functional role, and its relation to host health remain unclear. Here, we present a comprehensive large-scale analysis of intra-species copy-number variation in the gut microbiome, introducing a rigorous computational pipeline for detecting such variation directly from shotgun metagenomic data. We uncover a large set of variable genes in numerous species and demonstrate that this variation has significant functional and clinically relevant implications. We additionally infer intra-species compositional profiles, identifying population structure shifts and the presence of yet uncharacterized variants. Our results highlight the complex relationship between microbiome composition and functional capacity, linking metagenome-level compositional shifts to strain-level variation.
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•A metagenomic data analysis pipeline allows strain-level gene copy-number inference•Copy-number variation (CNV) is widespread across many prevalent human gut species•CNV involves mostly environment-related functions and is associated with disease•Strain-level population structure reveals known and uncharacterized strains
Extensive strain-level variation is detected in the human gut microbiome, with differences in gene copy-number impacting specific adaptive functions and linked to obesity and inflammatory bowel disease.
The low-grade oral infection chronic periodontitis (CP) has been implicated in coronary artery disease risk, but the mechanisms are unclear. In this study, a pathophysiological role for blood ...dendritic cells (DCs) in systemic dissemination of oral mucosal pathogens to atherosclerotic plaques was investigated in humans. The frequency and microbiome of CD19(-)BDCA-1(+)DC-SIGN(+) blood myeloid DCs (mDCs) were analyzed in CP subjects with or without existing acute coronary syndrome and in healthy controls. FACS analysis revealed a significant increase in blood mDCs in the following order: healthy controls < CP < acute coronary syndrome/CP. Analysis of the blood mDC microbiome by 16S rDNA sequencing showed Porphyromonas gingivalis and other species, including (cultivable) Burkholderia cepacia. The mDC carriage rate with P. gingivalis correlated with oral carriage rate and with serologic exposure to P. gingivalis in CP subjects. Intervention (local debridement) to elicit a bacteremia increased the mDC carriage rate and frequency in vivo. In vitro studies established that P. gingivalis enhanced by 28% the differentiation of monocytes into immature mDCs; moreover, mDCs secreted high levels of matrix metalloproteinase-9 and upregulated C1q, heat shock protein 60, heat shock protein 70, CCR2, and CXCL16 transcripts in response to P. gingivalis in a fimbriae-dependent manner. Moreover, the survival of the anaerobe P. gingivalis under aerobic conditions was enhanced when within mDCs. Immunofluorescence analysis of oral mucosa and atherosclerotic plaques demonstrate infiltration with mDCs, colocalized with P. gingivalis. Our results suggest a role for blood mDCs in harboring and disseminating pathogens from oral mucosa to atherosclerosis plaques, which may provide key signals for mDC differentiation and atherogenic conversion.
, the keystone pathogen in chronic periodontitis, was identified in the brain of Alzheimer's disease patients. Toxic proteases from the bacterium called gingipains were also identified in the brain ...of Alzheimer's patients, and levels correlated with tau and ubiquitin pathology. Oral
infection in mice resulted in brain colonization and increased production of Aβ
, a component of amyloid plaques. Further, gingipains were neurotoxic in vivo and in vitro, exerting detrimental effects on tau, a protein needed for normal neuronal function. To block this neurotoxicity, we designed and synthesized small-molecule inhibitors targeting gingipains. Gingipain inhibition reduced the bacterial load of an established
brain infection, blocked Aβ
production, reduced neuroinflammation, and rescued neurons in the hippocampus. These data suggest that gingipain inhibitors could be valuable for treating
brain colonization and neurodegeneration in Alzheimer's disease.
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