Cytokines mediate the balance between protective and destructive immunity in periodontitis. We sought to investigate the role of IL-33 in periodontitis. The expression of IL-33 in gingival tissue ...from healthy controls (n = 10) and patients with chronic periodontitis (n = 17) was investigated. Based on a murine model of periodontal disease, the function of IL-33 was determined first by administration of exogenous IL-33 and second by inhibition of IL-33 signaling using mice deficient in the IL-33 receptor ST2. Alveolar bone level, serum antibody, and lymphocyte responses were assessed in the murine model. Expression of IL-33 and ST2 was elevated in gingival tissues from patients with chronic periodontitis as compared with healthy tissues (P < 0.05). Similarly, Il33 expression was higher in periodontal tissues of Porphyromonas gingivalis–infected mice as compared with sham-infected controls (P < 0.05). IL-33 treatment of P. gingivalis–infected mice significantly exacerbated alveolar bone loss when compared with infection or IL-33 treatment alone (P < 0.001). Conversely, P. gingivalis infection–induced alveolar bone loss was attenuated in mice lacking ST2. The percentages of T and B lymphocytes expressing nuclear factor κB ligand (RANKL) in the gingival tissues and T lymphocytes expressing RANKL in the cervical draining lymph nodes were higher in IL-33-treated P. gingivalis–infected mice versus phosphate buffered saline–treated P. gingivalis–infected controls (all P < 0.001). Targeting the RANKL pathway by osteoprotegerin administration abrogated periodontal bone destruction in P. gingivalis–infected, IL-33-treated mice. These data demonstrate a previously unrecognized role for IL-33 in exacerbating bone loss in a RANKL-dependent manner in the context of bacterial infection and suggest that this pathway may be amenable to manipulation as a novel therapeutic target in periodontitis.
Background: Human intestine microbiota are known to be directly and indirectly altered during some diseases such as kidney complications. Bacteroides is considered as the main and the most abundant ...phylum among human gut microbiota, which has been classified as enterotype 1. This study aimed to assess the abundance of Bacteroides spp. in fecal flora of end-stage renal disease (ESRD) and chronic kidney disease (CKD) patients and compare it with the Bacteroides composition among fecal flora of healthy individual. Methods: Fresh fecal samples were collected from 20 CKD/ESRD patients and 20 healthy individual without any kidney complications. The pure microbial DNA was extracted by QIAamp Stool Mini Kit from stool samples. MiSeq system was used to analyze the intestinal composition by next generation sequencing method. Results: A number of 651 bacterial strains were isolated and identified from 40 fecal samples of both patients and healthy groups. Bioinformatics analysis defined 18 different types of Bacteroides species which included 2.76% of all strains. Statistical analysis showed no significant difference between study groups (P>0.05). In both healthy and patient groups three species including B. dorei, B. uniformis, and B. ovatus have allocated the most abundance to themselves. The lowest abundance was related to B. eggerthii, A. furcosa and B. barnesiae among CKD/ESRD patients and A. furcosa, B. barnesiae, and B. coprocola had the lowest abundance among healthy people. Conclusion: This study indicates despite all previous evidence of Bacteroides role in gut microbiota, it had no different distribution between healthy persons and CKD/ESRD patients.
Periodontitis is a common chronic inflammatory disease that is initiated by a complex microbial biofilm that poses significant health and financial burdens globally. Porphyromonas gingivalis is a ...predominant pathogen that maintains chronic inflammatory periodontitis. Toll-like receptors (TLRs) play an important role in periodontitis by recognizing pathogens and maintaining tissue homeostasis. Deficiencies in TLR expression and downstream signaling may reduce the host’s innate defenses against pathogens, leading to bacterial persistence and exacerbated inflammation, which are now being better appreciated in disease pathologies. In the case of periodontitis, gingival epithelial cells form the first line of defense against pathogens. Innate immune dysregulation in these cells relates to severe disease pathology. We recently identified a blunted TLR2 expression in certain gingival epithelial cells expressing diminished cytokine signaling upon P. gingivalis stimulation. Upon detailed analysis of the TLR2 promoter CpG Island, we noted higher CpG methylation in this dysregulated cell type. When these cells were treated with DNA methyltransferase inhibitor, TLR2 mRNA and cytokine expression were significantly increased. If TLR2 expression plasmid was ectopically expressed in dysfunctional cells prior to P. gingivalis stimulation, the cytokine expression was increased, confirming the requirement of TLR2 in the P. gingivalis–mediated inflammatory response. We designed a chronic in vitro infection model to test if P. gingivalis can induce DNA methylation in normal gingival epithelial cells that express higher TLR2 upon agonist stimulation. Chronic treatment of normal epithelial cells with P. gingivalis introduced de novo DNA methylation within the cells. In addition, increased DNA methylation was observed in the gingiva of mice infected with P. gingivalis in a periodontitis oral gavage model. Moreover, tissues obtained from periodontitis patients also exhibited differential TLR2 promoter methylation, as revealed by bisulfite DNA sequencing. Taken together, DNA methylation of TLR2 can modulate host innate defense mechanisms that may confer increased disease susceptibility.
The chicken gastrointestinal tract (GIT) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. For the first time, the ...present study analysed dietary effects on the protein inventory of the microbiome in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1-D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorous (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increased with the amount of MP while proteins of Lactobacillaceae were more abundant in the MP-lacking diets. Classification of the identified proteins indicated a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Data are available via ProteomeXchange with identifier PXD003805.
is a keystone pathogen that contributes to periodontal pathogenesis by disrupting host-microbe homeostasis and promoting dysbiosis. The virulence of
likely reflects an alteration in the lipid A ...composition of its lipopolysaccharide (LPS) from the penta-acylated (
LPS
) to the tetra-acylated (
LPS
) form. Mast cells play an important role in periodontitis, but the mechanisms of their activation and regulation remain unknown. The expression of epithelium- and neutrophil-derived host defense peptides (HDPs) (LL-37 and human β-defensin-3), which activate mast cells via Mas-related G protein-coupled receptor X2 (MRGPRX2), is increased in periodontitis. We found that MRGPRX2-expressing mast cells are present in normal gingiva and that their numbers are elevated in patients with chronic periodontitis. Furthermore, HDPs stimulated degranulation in a human mast cell line (LAD2) and in RBL-2H3 cells stably expressing MRGPRX2 (RBL-MRGPRX2).
LPS
caused substantial inhibition of HDP-induced mast cell degranulation, but
LPS
had no effect. A fluorescently labeled HDP (FAM-LL-37) bound to RBL-MRGPRX2 cells, and
LPS
inhibited this binding, but
LPS
had no effect. These findings suggest that low-level inflammation induced by HDP/MRGPRX2-mediated mast cell degranulation contributes to gingival homeostasis but that sustained inflammation due to elevated levels of both HDPs and MRGPRX2-expressing mast cells promotes periodontal disease. Furthermore, differential regulation of HDP-induced mast cell degranulation by
LPS
and
LPS
may contribute to the modulation of disease progression.
A number of studies have shown that the outer membrane protein FomA found in
Fusobacterium nucleatum
demonstrates great potential as an immune target for combating periodontitis.
Lactobacillus ...acidophilus
is a useful antigen delivery vehicle for mucosal immunisation, and previous studies by our group have shown that
L. acidophilus
acts as a protective factor in periodontal health. In this study, making use of the immunogenicity of FomA and the probiotic properties of
L. acidophilus
, we constructed a recombinant form of
L. acidophilus
expressing the FomA protein and detected the FomA-specific IgG in the serum and sIgA in the saliva of mice through oral administration with the recombinant strains. When serum containing FomA-specific antibodies was incubated with the
F. nucleatum in vitro
, the number of
Porphyromonas gingivalis
cells that coaggregated with the
F. nucleatum
cells was significantly reduced. Furthermore, a mouse gum abscess model was successfully generated, and the range of gingival abscesses in the immune mice was relatively limited compared with the control group. The level of IL-1β in the serum and local gum tissues of the immune mice was consistently lower than in the control group. Our findings indicated that oral administration of the recombinant
L. acidophilus
reduced the risk of periodontal infection with
P. gingivalis
and
F. nucleatum.
Summary
Epidemiological studies support that chronic periodontal infections are associated with an increased risk of cardiovascular disease. Previously, we reported that the periodontal pathogen ...Porphyromonas gingivalis accelerated atherosclerotic plaque formation in hyperlipidemic apoE–/– mice, while an isogenic fimbria‐deficient (FimA‐) mutant did not. In this study, we utilized 41 kDa (major) and 67 kDa (minor) fimbria mutants to demonstrate that major fimbria are required for efficient P. gingivalis invasion of human aortic endothelial cells (HAEC). Enzyme‐linked immunosorbent assay (ELISA) revealed that only invasive P. gingivalis strains induced HAEC production of pro‐inflammatory molecules interleukin (IL)‐1β, IL‐8, monocyte chemoattractant protein (MCP)‐1, intracellular adhesion molecule (ICAM)‐1, vascular cellular adhesion molecule (VCAM)‐1 and E‐selectin. The purified native forms of major and minor fimbria induced chemokine and adhesion molecule expression similar to invasive P. gingivalis, but failed to elicit IL‐1β production. In addition, the major and minor fimbria‐mediated production of MCP‐1 and IL‐8 was inhibited in a dose‐dependent manner by P. gingivalis lipopolysaccharide (LPS). Both P. gingivalis LPS and heat‐killed organisms failed to stimulate HAEC. Treatment of endothelial cells with cytochalasin D abolished the observed pro‐inflammatory MCP‐1 and IL‐8 response to invasive P. gingivalis and both purified fimbria, but did not affect P. gingivalis induction of IL‐1β. These results suggest that major and minor fimbria elicit chemokine production in HAEC through actin cytoskeletal rearrangements; however, induction of IL‐1β appears to occur via a separate mechanism. Collectively, these data support that invasive P. gingivalis and fimbria stimulate endothelial cell activation, a necessary initial event in the development of atherogenesis.
The determinants of HIV-associated cardiovascular disease (CVD) are not well understood. Periodontal disease (PD) has been linked to CVD but this connection has not been examined in HIV infection. We ...followed a cohort of HIV-infected adults to ascertain whether PD was associated with carotid artery intima media thickness (IMT) and brachial artery flow-mediated dilation (FMD). We performed a longitudinal observational study of HIV-infected adults on HAART for <2 years with no known heart disease. PD was characterized clinically and microbiologically. Cardiovascular disease was assessed by IMT/FMD. Linear mixed models assessed cross-sectional and longitudinal associations between PD and FMD/IMT. Forty three HIV(+) adults completed a median of 24 (6-44) months on the study. Defining delta to be the change in a variable between baseline and a follow-up time, longitudinally, on average and after adjusting for change in time, CVD-specific and HIV-specific potential confounding covariates, a 1-log(10) increase in delta Porphyromonas gingivalis was associated with a 0.013 mm increase in delta IMT (95% CI: 0.0006-0.0262; p=0.04). After adjusting for the same potential confounding covariates, a 10% increase in delta gingival recession was associated with a 2.3% increase in delta FMD (95% CI: 0.4-4.2; p=0.03). In a cohort of HIV-infected adults, an increase in subgingival Porphyromonas gingivalis, a known periodontal pathogen, was significantly associated with longitudinal increases in IMT, while increased gingival recession, which herein may represent PD resolution, was significantly associated with longitudinal improvement in FMD. In the context of HIV infection, PD may contribute to CVD risk. Intervention studies treating PD may help clarify this association.
A wide variety of infections, including bacteria, viruses, fungi and protozoa occur in the immunocompromised condition associated with human immunodeficiency virus type 1 (HIV-1) infection and ...acquired immunodeficiency syndrome (AIDS). Although these opportunistic infections are believed to arise as an effect of the immunodeficiency, these microbes sometimes promote the disease progression of HIV-1 infection by enhancing viral replication or modulating host immune responses. Here we review the experimental and clinical evidence supporting such causal relationships associated with periodontogenic bacteria. Periodontal disease, caused by subgingival infection with oral anaerobic bacteria, typically Porphyromonas gingivalis (P. gingivalis) belonging to the phylum Bacteroidetes, is found worldwide and is one of the most prevalent microbial diseases of mankind. Emerging evidence implicates the involvement of P. gingivalis infection in the progression of HIV-1 infection. We demonstrate that P. gingivalis can induce HIV-1 reactivation via chromatin modification, and that the bacterial metabolite butyric acid produced in anaerobic conditions is responsible for this effect. These findings suggest that periodontal diseases could act as a risk factor for HIV-1 reactivation in infected individuals and might contribute to AIDS progression. Furthermore, it would imply that prevention and early treatment of periodontitis involving P. gingivalis infection could effectively block further clinical progression of AIDS.
We investigated the persistence of feces-derived
Bacteroidales cells and their DNA in seawater under natural conditions using an optimized chemical method based on co-extraction of nucleic acids with ...propidium monoazide (PMA), which interferes with PCR amplification of molecular markers from extracellular DNA and dead bacterial cells. The previously validated
Bacteroidales assays BacUni-UCD, BacHum-UCD, BacCow-UCD, and BacCan-UCD were utilized to determine concentrations of
Bacteroidales genetic markers targeting all warm-blooded animals, humans, cows and dogs, specifically, over a period of 24
d. Microcosms containing mixed feces in dialysis tubing were exposed to seawater under flow-through conditions at ambient temperature in the presence and absence of sunlight. Using a two-stage plus linear decay model, the average
T
99 (two-log reduction) of host-specific
Bacteroidales cells was 28
h, whereas that of host-specific
Bacteroidales DNA was 177
h. Natural sunlight did not affect the survival of uncultivable
Bacteroidales cells and their DNA with the exception of the BacCow-UCD marker.
Bacteroidales DNA, as measured by quantitative PCR (qPCR) without PMA, persisted for as long as 24
d at concentrations close to the limit of detection. Culturable
Enterococcus cells were detected for only 70
h, whereas
Enterococcus cells measured by qPCR with and without PMA persisted for 450
h. In conclusion, measuring
Bacteroidales DNA without differentiating between intact and dead cells or extracellular DNA may misinform about the extent of recent fecal pollution events, particularly in the case of multiple sources of contamination with variable temporal and spatial scales due to the relatively long persistence of DNA in the environment. In contrast, applying qPCR with and without PMA can provide data on the fate and transport of fecal
Bacteroidales in water, and help implement management practices to protect recreational water quality.
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