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Comprehensive analysis of cytokine levels in serum from SKG mice. Cytokine levels were measured in comprehensively serum (n 5 6). Serum from six groups of SKG mice was analysed by the Bio-Plex system (Bio-Plex Pro mouse 23-plex assay kit). Cytokine levels in all serum samples used in this study were examined at the same time in duplicate. Distribution of serum molecules in the narcolepsy group was compared with that in the healthy control group using Student's t-test (two-tailed test).
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Epidemiological studies have linked periodontitis to rheumatoid arthritis (RA). Porphyromonas gingivalis (Pg) was recently reported to produce citrullinated protein (CP) and increase anti-cyclic CP antibody (ACPA), both of which have been identified as causative factors of RA. In the present study, we determined the effects of Pg infection on the e...
Citations
... Studies in recent years have found that P.gingivalis is not only one of the main important pathogenic bacteria in the development of periodontitis, but also closely related to systemic diseases including rheumatoid arthritis (RA) [40][41][42][43][44][45], cardiovascular disease [46][47][48][49][50][51], diabetes [36,42,52] and Alzheimer's disease (AD) [53][54][55][56][57]. The imbalance of oral microecology caused by the abnormal increase in the relative abundance of P. gingivalis can not only cause the destruction of local tissues in the oral cavity, but also damage distant tissues and organs far away from the primary lesions [16,47,[58][59][60][61]. P.gingivalis produces gingivain that can cause local tissue damage, disrupt the host's antibacterial defense, and lead to excessive growth and dissemination of symbiotic bacteria in the oral and intestinal tract. ...
Aim: Non-alcoholic fatty liver disease is characterized by diffuse hepatic steatosis and has quickly risen to become the most prevalent chronic liver disease. Its incidence is increasing yearly, but the pathogenesis is still not fully understood. Porphyromonas gingivalis (P. gingivalis) is a major pathogen widely prevalent in periodontitis patients. Its infection has been reported to be a risk factor for developing insulin resistance, non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and metabolic syndrome. The aim of this review is to evaluate the association between P. gingivalis infection and NAFLD, identify the possible etiopathogenetic mechanisms, and raise public awareness of oral health to prevent and improve NAFLD.Methods: After searching in PubMed and Web of Science databases using ‘Porphyromonas gingivalis’, ‘non-alcoholic fatty liver disease’, and ‘hepatic steatosis’ as keywords, studies related were compiled and examined.Results: P. gingivalis infection is a direct risk factor for NAFLD based on clinical and basic research. Moreover, it induces systematic changes and systemic abnormalities by disrupting metabolic, inflammatory, and immunologic homeostasis.Conclusion: P. gingivalis-odontogenic infection promotes the occurrence and development of NAFLD. Further concerns are needed to emphasize oral health and maintain good oral hygiene for the prevention and treatment of NAFLD.
... Most of these animal studies demonstrated the involvement of P. gingivalis infection in the induction and progression of experimental arthritis. This appeared to be related to increased levels of protein citrullination through peptidylarginine deiminase (PAD) from P. gingivalis (PPAD) [38,41,45,49,53,57] and increased levels of T helper 17 (Th17) cell differentiation and subsequent inflammatory responses and induction of osteoclastogenesis [39,40,[42][43][44]48]. In addition, an alteration of gut barrier, microbiota, and immune profile toward Th17 was noted [47,56,58]. ...
... Periodontitis-induced NETs also produce carbamylated protein (CarP) and anti-CarP antibody [85,107,110,126], reacting with CarP, followed by joint inflammation and the development of RA. P. gingivalis infection promotes Th17 cell development and the Th17-driven response of cytokines and chemokines [39,40,[42][43][44]48], generates active complement C5a by Rgp [52], and causes FimA-mediated adhesion to immune cells and subsequent bacterial translocation to the joints [50] and lipopolysaccharide (LPS)-induced cytokine synthesis [111]. Oral infection with P. gingivalis showing the influx of LPS into the gut can cause intestinal dysbiosis, leading to a shift in the immune profile toward Th17 [47,56,58,111,134]. ...
Rheumatoid arthritis (RA) is characterized by chronic inflammatory destruction of joint tissue and is caused by an abnormal autoimmune response triggered by interactions between genetics, environmental factors, and epigenetic and posttranslational modifications. RA has been suggested to be interrelated with periodontitis, a serious form or stage of chronic inflammatory periodontal disease associated with periodontopathic bacterial infections, genetic predisposition, environmental factors, and epigenetic influences. Over the last decade, a number of animal and clinical studies have been conducted to assess whether or not periodontitis and associated periodontopathic bacteria constitute risk factors for RA. The present review introduces recent accumulating evidence to support the associations of periodontitis and periodontopathic bacteria with the risk of RA or the outcome of RA pharmacological treatment with disease-modifying antirheumatic drugs. In addition, the results from intervention studies have suggested an improvement in RA clinical parameters after nonsurgical periodontal treatment. Furthermore, the potential causal mechanisms underlying the link between periodontitis and periodontopathic bacteria and RA are summarized.
... These results suggest that substances from oral and gut microbiota may influence disease activity in RA patients [98]. Many studies have demonstrated that P. gingivalis administration exacerbated RA, whether P. gingivalis was administered before the onset of RA [99][100][101][102] or concurrently with RA [46,103] or after RA induction [102]. P. gingivalis is more pro-arthritic compared to other periopathogens such as Prevotella intermedia [38] and F. nucleatum [102] or commensal bacterium Bacteroides thetaiotaomicron [74]. ...
Over the past two decades, the importance of microbiota in health and disease has become evident. The human gut microbiota and oral microbiota are the largest and second-largest microbiome in the human body, respectively, and they are physically connected as the oral cavity is the beginning of the digestive system. Emerging and exciting evidence has shown complex and important connections between gut microbiota and oral microbiota. The interplay of the two microbiomes may contribute to the pathological processes of many diseases, including diabetes, rheumatoid arthritis, nonalcoholic fatty liver disease, inflammatory bowel disease, pancreatic cancer, colorectal cancer, and so on. In this review, we discuss possible routes and factors of oral microbiota to affect gut microbiota, and the contribution of this interplay between oral and gut microbiota to systemic diseases. Although most studies are association studies, recently, there have been increasing mechanistic investigations. This review aims to enhance the interest in the connection between oral and gut microbiota, and shows the tangible impact of this connection on human health.
... The sequences of the primer pairs used for quantitation of IL-6; TLR2; OSCAR; nuclear factor of activated T cells, cytoplasmic 1 (NFATc1); c-Fos; cathepsin K (CatK); matrix metalloproteinase-9 (MMP-9); DC-STAMP; and β-actin mRNA expression are listed in supplemental Table S1. The primer sequences are based on previous reports [20,22,23]. ...
... The upper jaws of the mice were collected at the end of the experiment (6 weeks) and maintained in 4% paraformaldehyde for 48 h, kept in 10% ethylene diamine tetrameric acid for 14 days to decalcify, and embedded in paraffin. Tissue sections (7 µm-thick) were stained with hematoxylin and eosin (HE) [23]. The severity of inflammation was scored using a previously published criteria [25]. ...
Periodontal disease is predominantly caused by the pathogenic bacterium Porphyromonas gingivalis that produces inflammation-inducing factors in the host. Eucommia ulmoides is a plant native to China that has been reported to reduce blood pressure, promote weight loss, and exhibit anti-inflammatory effects. Geniposidic acid (GPA) is the major component of E. ulmoides. Herein, we investigated the effects of GPA on P. gingivalis-induced periodontitis by measuring the inflammatory responses in human gingival epithelial cells (HGECs) after P. gingivalis stimulation and GPA addition in a P. gingivalis-induced periodontitis mouse model. We found that GPA addition suppressed interleukin (IL)-6 mRNA induction (33.8% suppression), IL-6 production (69.2% suppression), toll-like receptor (TLR) 2 induction, and mitogen-activated protein kinase (MAPK) phosphorylation in HGECs stimulated by P. gingivalis. Inoculation of mice with GPA inhibited P. gingivalis-induced alveolar bone resorption (25.6% suppression) by suppressing IL-6 and TLR2 production in the serum and gingiva. GPA suppressed osteoclast differentiation of bone marrow cells induced by M-CSF and sRANKL in mice (56.7% suppression). GPA also suppressed the mRNA expression of OSCAR, NFATc1, c-Fos, cathepsin K, and DC-STAMP. In summary, GPA exerts an anti-inflammatory effect on periodontal tissue and may be effective in preventing periodontal disease.
... Inhibition of protease activity Bania et al., 2008 Widziolek et al. (2016) employed Zebrafish larvae to showcase the link between Rgp and cardiovascular diseases in vivo. P. gingivalis travelled to different parts of the host via bloodstream and invaded vascular barriers, allowing their invasion into the surrounding tissue. ...
Porphyromonas gingivalis is a major pathogenic bacterium involved in the pathogenesis of periodontitis. Citrullination has been reported as the underlying mechanism of the pathogenesis, which relies on the interplay between two virulence factors of the bacterium, namely gingipain R and the bacterial peptidyl arginine deiminase. Gingipain R cleaves host proteins to expose the C-terminal arginines for peptidyl arginine deiminase to citrullinate and generate citrullinated proteins. Apart from carrying out citrullination in the periodontium, the bacterium is found capable of citrullinating proteins present in the host synovial tissues, atherosclerotic plaques and neurons. Studies have suggested that both virulence factors are the key factors that trigger distal effects mediated by citrullination, leading to the development of some non-communicable diseases, such as rheumatoid arthritis, atherosclerosis, and Alzheimer’s disease. Thus, inhibition of these virulence factors not only can mitigate periodontitis, but also can provide new therapeutic solutions for systematic diseases involving bacterial citrullination. Herein, we described both these proteins in terms of their unique structural conformations and biological relevance to different human diseases. Moreover, investigations of inhibitory actions on the enzymes are also enumerated. New approaches for identifying inhibitors for peptidyl arginine deiminase through drug repurposing and virtual screening are also discussed.
... For mass spectrometry, pre-enrichment of the sample for citrullinated proteins is often needed, which relies on either use of anticitrulline antibodies or through chemical modification of the samples followed by enrichment with ligands similar to the probe recognition methods. Among these approaches, the anticitrullinated protein antibodies are the most widely used for different applications including liquid fluid sample detection (21), Western blotting (22), immunofluorescence (11,23), immunohistochemistry (24,25) and immunological enrichment (26). However, most of the antibodies used are polyclonal antibodies (27) or monoclonal antibodies (mAbs) (28) obtained by immunization with citrullinated-protein conjugates. ...
Background
Citrullination is a post-translational protein modification linked to the occurrence and development of a variety of diseases. The detection of citrullinated proteins is predominately based on antibody detection although currently available reagents demonstrate detection bias according to the environmental context of the citrullinated residues. This study aimed to develop improved antibody reagents capable of detecting citrullinated residues in proteins in an unbiased manner.
Methods
BALB/c mice were sequentially immunized using citrulline conjugates with different carrier proteins, and specific monoclonal antibodies (mAbs) identified by primary screening using citrulline-conjugated proteins unrelated to the immunogen. Secondary screening was performed to identify mAbs whose reactivity could be specifically blocked by free citrulline, followed by identification and performance assessment.
Results
Two mAbs, 22F1 and 30G2, specifically recognizing a single citrulline residue were screened from 22 mAbs reacting with citrulline conjugates. Compared with commercially available anti-citrulline antibodies (AB6464, AB100932 and MABN328), 22F1 and 30G2 demonstrated significantly higher reactivity as well as a broader detection spectrum against different citrullinated proteins. 22F1 and 30G2 also had higher specificity than commercial antibodies and overall better applicability to a range of different immunoassays.
Conclusion
Two mAbs specifically recognizing a single citrulline residue were successfully produced, each possessing good specificity against different citrullinated proteins. The improved utility of these reagents is expected to make a strong contribution to protein citrullination-related research.
... Moreover, it was shown recently that therapeutic eradication of P. gingivalis with chlorhexidine and metronidazole reduced the incidence and alleviated the severity of collagen-induced arthritis comparable to methotrexate in a murine model of periodontitis.73 As rheumatoid arthritis is strongly associated with genetic risk factors, it is unsurprising that periopathogen infection has a significant impact on rheumatoid arthritis development in mice strains genetically susceptible for rheumatoid arthritis, such as SKG,74 HLA-DR1 humanized C57BL/6 mice, 12 DBA/1JJmsSlc,69 DBA/1J, 67 DBA/1 × 10.Q F1, 71 and B10.RIII. 72 Together, these results indicate that periodontitis may be the underlying condition facilitating rheumatoid arthritis development in genetically susceptible humans. ...
Research in recent decades has brought significant advancements in understanding of the molecular basis of the etiology of autoimmune diseases, including rheumatoid arthritis, a common systemic disease in which an inappropriate or inadequate immune response to environmental challenges leads to joint destruction. Recent studies have indicated that the classical viewpoint of the immunological processes underpinning the pathobiology of rheumatoid arthritis is restricted and needs to be expanded to include a more holistic and interdisciplinary approach incorporating bacteria‐induced inflammatory reactions as an important pathway in rheumatoid arthritis etiology. Here, we discuss in detail data showing the clinical and molecular association of rheumatoid arthritis development with periodontal diseases. We also describe the unique role of periopathogens, which have been proposed to be crucial in the initiation and progression of this autoimmune pathological disorder.
... RA-related autoantibodies against these pathogens are stimulated in different ways. PPAD-an enzyme with citrullination activity against P.g-and LtxA-an enzyme with hyper citrullination activity via neutrophil osmotic lysis to A.aare known as essential factors to sustain RA development [11][12][13]. ...
... Furthermore, we found that RA compared with HCs show a higher prevalence of humoral response against peptides derived by periodontal pathogens, which was statistically meaningful for the anti-RgpA IgG peptide. This is in line with findings from epidemiological studies suggesting a potential pathogenic link between periodontitis and RA [11,34,35]. P. gingivalis and A. actinomycetecomitans are the most common reported pathogens in periodontitis, and they can contribute to RA autoantibody production through various mechanisms: directly by post-translation modification of human protein (by the PPAD enzyme of P. gingivalis) or indirectly by neutrophil osmotic lysis (leukotoxin of Aa) [9,[11][12][13]. ...
... This is in line with findings from epidemiological studies suggesting a potential pathogenic link between periodontitis and RA [11,34,35]. P. gingivalis and A. actinomycetecomitans are the most common reported pathogens in periodontitis, and they can contribute to RA autoantibody production through various mechanisms: directly by post-translation modification of human protein (by the PPAD enzyme of P. gingivalis) or indirectly by neutrophil osmotic lysis (leukotoxin of Aa) [9,[11][12][13]. In this study, we found a positive significant correlation between anti-LtxA2 and anti-Kpg, and also, anti-LtxA1 and anti-LtxA2 with RF, suggesting that P. gingivalis and A. actinomycetecomitans may cooperate in inducing immunity against periodontal and synovial self-antigens. ...
Background/objective:
Chronic humoral immune response against multiple microbial antigens may play a crucial role in the etiopathogenesis of rheumatoid arthritis (RA). We aimed to assess the prevalence and magnitude of antibody response against various bacterial and viral immunogen peptides in the sera of RA patients compared with the general population.
Methods:
Polyclonal IgG antibodies (Abs) specific for peptides derived from Porphyromonas gingivalis (RgpA, Kpg), Aggregatibacter actinomycetemcomitans (LtxA1, LtxA2), Mycobacterium avium subsp. paratuberculosis (MAP4027), Epstein-Barr virus (EBNA1, EBVBOLF), and human endogenous retrovirus (HERV-W env-su) were detected by ELISA in serum samples from 148 consecutive RA patients and 148 sex and age-matched healthy controls (HCs). In addition, the presence of a relationship between the positivity and the titer of antibodies and RA descriptors was explored by bivariate correlation analysis.
Results:
RA patients exhibit a higher prevalence of humoral immune response against all tested peptides compared to HCs with a statically significant difference for MAP4027 (30.4% vs. 10.1%), BOLF (25.7% vs. 8.1%), RgpA (24.3% vs. 9.4%), HERV W-env (20.3% vs. 9.4%), and EBNA1 (18.9% vs. 9.4%) peptides. Fifty-three (35.8%) out of 148 RA serum and 93 (62.8%) out of 148 HCs were negative for all pathogen-derived peptides. There was a significant correlation between OD values obtained by ELISA test against all peptides (p < 0.0001). We also found an increased titer and prevalence of Abs against LtxA1 and LtxA2 in seropositive vs. seronegative RF (p = 0.019, p = 0.018).
Conclusion:
This study demonstrates a significantly increased humoral response against multiple pathogens in patients with RA and implies that they could be an important factor in the pathogenesis of the disease. Therefore, the role of each individual pathogen in RA needs to be further investigated.
... lead to the initiation and progression of rheumatoid arthritis. [74][75][76][77][78][79][80][81][82][83][84][85][86][87] P. gingivalis produces a specific peptidyl arginine deiminase, P. gingivalis peptidil-arginine deiminase, 8,88 which can citrullinate human proteins and may increase the probability of greater formation of anti-cyclic citrullinated peptide. In fact, P. gingivalis peptidil-arginine deiminase may citrullinate peptides that are released from P. gingivalis gingipain-mediated degradation of fibrinogen and alphaenolase, 42 or it may promote self-citrullination. 42 Other studies have shown that Tannerella forsythia, 95 ...
Rheumatoid arthritis and periodontitis are chronic inflammatory diseases defined respectively by the destruction of the articular cartilage and tooth‐supporting periodontal tissues. Although the epidemiologic evidence for an association between these two diseases is still scarce, there is emerging scientific information linking specific bacterial periodontal pathogens, such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, in the citrullination process, leading to autoantibody formation and compromised immunotolerance of the susceptible patient to rheumatoid arthritis. In this review, we update the existing information on the evidence, not only regarding the epidemiologic association, but also the biologic mechanisms linking these two diseases. Finally, we review information emerging from intervention studies evaluating whether periodontal treatment could influence the initiation and progression of rheumatoid arthritis.
... 24 57 In another model, infection with P. gingivalis expressing a bacterial PAD enzyme has been shown to trigger arthritis and an ACPA response that correlated with local and systemic bone loss 58 and to exacerbate arthritis development in ZAP-70 mutant (SKG) mice with increased production of ACPA. 59 Importantly, citrullinated peptides could also downmodulate disease activity if introduced in the absence of adjuvant and before the onset of inflammation, as shown in the murine collagen-induced arthritis model. 60 Similarly, in a rat adjuvant-induced arthritis model, subcutaneous injection of citrullinated peptides very early after disease initiation could reduce disease severity, likely through an increase in regulatory T cell/TH17 cell ratio and an effect on T cell apoptosis. ...
Epidemiological findings suggest a potential role for anti-citrullinated protein antibodies (ACPAs) in rheumatoid arthritis (RA) pathogenesis. ACPA-positive RA is associated with unique genetical and environmental risk factors, in contrast to seronegative RA. ACPA-positive healthy individuals are at risk of developing RA and can develop joint pain and bone loss already before disease onset. ACPA injection triggered bone loss and pain-like behaviour in mice and, in the presence of additional arthritis inducers, exacerbated joint inflammation. In cell culture experiments, ACPAs could bind to and modulate a variety of cellular targets, such as macrophages, osteoclasts, synovial fibroblasts, neutrophil granulocytes, mast cells, dendritic cells and platelets, further underlying a potential role for these autoantibodies in triggering pathogenic pathways and providing clues for their mechanisms of action. Patient-derived ACPA clones have been characterised by unique cellular effects and multiple ways to act on the target cells. ACPAs might directly induce stimulatory signals by ligating key citrullinated cell surface molecules or, alternatively, act as immune complexes on Fc receptors and potentially other molecules that recognise carbohydrate moieties. On the contrary to experimentally manufactured ACPA clones, patient-derived ACPAs are highly promiscuous and cross-reactive, suggesting a simultaneous binding to a range of functionally relevant and irrelevant targets. Moreover, several ACPA clones recognise carbamylated or acetylated targets as well. These features complicate the identification and description of ACPA-induced pathogenic mechanisms. In the current review, we summarise recent data on the functional properties of patient-derived ACPAs and present mechanistic models on how these antibodies might contribute to RA pathogenesis.
