Porphyromonas gulae lipopolysaccharide elicits inflammatory responses through toll-like receptor 2 and 4 in human gingivalis epithelial cells

Porphyromonas gulae and canine periodontal disease: Current understanding and future directions

Porphyromonas gulae has emerged as a notable pathogen in canine periodontal disease, akin to Porphyromonas gingivalis in human periodontitis. This review examines the initial isolation, phylogenetic analysis, habitat, host range, relationships with host health status and age, and key pathogenic determinants, including fimbriae, proteases, citrullinating enzyme, and lipopolysaccharide. Control strategies discussed include polyphosphate to disrupt haeme/iron utilization, clindamycin with interferon alpha to reduce bacterial load and enhance the immune response, and a protease inhibitor. Further research is needed to understand strain-level diversity of virulence factors and interactions between P. gulae and other oral bacteria, particularly Fusobacterium nucleatum, a common pathogen in both dogs and humans. The potential for interspecies transmission between dogs and humans warrants further research into these interactions. Extensive in vivo studies across various breeds are crucial to validate the effectiveness of proposed treatment strategies. This review emphasizes P. gulae's role in periodontal health and disease, setting the stage for future research and improved management of canine periodontal disease.

Intraoral treatment of persimmon tannin, a polyphenol extracted from persimmon, significantly ameliorates gingivitis, plaque and halitosis via directly influence the periodontal bacteria Porphyromonasgulae

BACKGROUND

As periodontal disease (PD) is an irreversible disorder, preventive dentistry in human and veterinary medicine has become pertinent. This study focused on persimmon tannin (PT) and examined its bactericidal, anti-halitosis, and anti-inflammatory effects by focusing on Porphyromonas gulae (P. gulae).

METHODS

The direct effects of PT on P. gulae were evaluated in vitro. Pro-inflammatory cytokines secretion induced by P. gulae in the macrophage cell lines were determined. A clinical study in dogs with P. gulae-associated PD was performed by one-month intraoral treatment with 0.1% PT-containing gel.

RESULTS

PT exhibited a significant bactericidal effect to P. gulae. The biofilm formation and methyl mercaptan generated by P. gulae was significantly decreased by PT even after a short exposure period. P. gulae-induced proinflammatory cytokine production in macrophage cell lines was inhibited by PT treatment in a dose-dependent manner. In a clinical study of dogs, intraoral treatment with 0.1% PT did not significantly influence the gingivitis and plaque scores, however, the concentrations of hydrogen sulfide and methyl mercaptan were also significantly decreased by the PT treatment. Although there was no anti-bacterial in vitro, P. gulae activity and DNA detection decreased with PT treatment.

CONCLUSIONS

These findings suggest that intraoral administration of PT can prevent PD.

Real-Time Polymerase Chain Reaction (PCR) Quantification of Periodontal Pathogenic Bacteria (Porphyromonas gulae, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) in Dogs

The present study investigated the molecular presence of 4 species of pathogenic periodontal bacteria (Porphyromonas gulae, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) using quantitative real-time polymerase chain reaction (PCR) in 230 household dogs with or without gingivitis, dental plaque and/or calculus. Overall, T. forsythia was most frequently present (77.8%), followed by P. gulae (50.9%), T. denticola (38.7%), and P. gingivalis (34.8%). A higher percentage of these bacteria was associated with factors such as age, grade of gingivitis, and an increase in dental plaque and/or calculus that indicated poor oral cleanliness. Even without a direct relation to gingivitis and plaque and/or calculus, these 4 species were consistently found not only in older dogs but also in younger ones. The results suggest that these bacteria are commonly present in household dogs, which puts them at risk of developing periodontal disease. Considering that 3 species of bacteria, excluding P. gulae, have zoonotic potential, it emphasizes the need for caution to prevent transmission between dogs and humans. Regarding overall bacterial DNA copy numbers, there was a wide range, with P. gulae having the most, followed by T. forsythia, P. gingivalis, and finally, T. denticola. The copy numbers did not always correlate with prevalence. The DNA copy numbers of T. forsythia were significantly lower in cases of higher-grade gingivitis and when there was poor oral cleanliness. These findings highlight the complexity of the interplay between bacterial type, prevalence, DNA copy numbers, and the oral health of household dogs.

Oral treatment with catechin isolated from Japanese green tea significantly inhibits the growth of periodontal pathogen Porphyromonas gulae and ameliorates the gingivitis and halitosis caused by periodontal disease in cats and dogs

It has been postulated that 90 % of cats and dogs develop periodontal disease by 1 year of age. Periodontal disease develops because of infection by multiple bacteria, including Porphyromonas gulae (P. gulae) and Porphyromonas gingivalis (P. gingivalis), resulting in severe gingivitis, halitosis, and bone lysis. Because periodontal disease is an irreversible disorder, preventive dentistry in veterinary medicine has become pertinent. This study examined the efficacy of catechin isolated from green tea by focusing on its bactericidal effects against P. gulae and P. gingivalis, inhibition of inflammation, and reduction in halitosis in dogs and cats with periodontal disease. The viability of P. gulae and P. gingivalis was significantly inhibited by catechin in a dose-dependent manner in vitro. P. gulae- and P. gingivalis-associated biofilm formation was also significantly suppressed by catechin, but the effect was not as drastic as the bactericidal effect. Hydrogen sulfide and methyl mercaptan generated by P. gulae and P. gingivalis were significantly decreased by catechin, even after a short exposure. Pro-inflammatory cytokine production and phosphorylation of P-38 and JNK induced by P. gulae were inhibited by catechin treatment in a dose-dependent manner. Treatment with 0.01892 % catechin-contained wet food for 1 month (30-35 days) significantly ameliorated halitosis and P. gulae activity, but had no impact on dental plaque and gingivitis. Our findings indicate that oral treatment with catechin can prevent periodontal diseases in both dogs and cats.

Role of fimbriae variations in Porphyromonas gulae biofilm formation

OBJECTIVES

Porphyromonas gulae is a major causative agent of periodontal disease in companion animals that possesses various virulence factors, including fimbriae, lipopolysaccharides, and proteases. P. gulae fimbriae are classified into three genotypes (A, B, and C) based on their nucleotide sequences. Type C fimbrial isolates have been reported to be more virulent than other fimA types, suggesting that different fimA types may aid in the regulation of periodontal pathogenesis. Detailed findings regarding the ability of P. gulae to form biofilms have yet to be reported. Here, we investigated the contributions of fimbrial genotypes in P. gulae biofilm formation.

METHODS

P. gulae and P. gingivalis biofilms were generated on plates and analyzed using confocal laser microscopy. Additionally, the biofilms formed were assessed by staining with crystal violet. Furthermore, the physical strength of P. gulae biofilms was examined by ultrasonication.

RESULTS

Biofilms formed by P. gulae type C were denser than those formed by types A and B. Moreover, the amount of biofilm formed by type C strains was significantly greater than that formed by type A and B strains, which was similar to the biofilms formed by P. gingivalis with type II fimbriae. Additionally, the physical strength of the type C biofilm was significantly greater than that of the other strains.

CONCLUSIONS

These results suggest that FimA variation may coordinate for biofilm formation. This is the first report on the observation and characterization of P. gulae biofilm formation.

The Effect of Subacute Oral Folic Acid Treatment on Growth of Porphyromonas gulae in Dogs

Periodontitis is one of the most prevalent infectious diseases in humans and animals. It is a multifactorial disease resulting in attachment loss and tooth loss. Therefore, preventive dentistry, such as daily teeth cleaning or providing dental chews from puppyhood is essential. This study aimed to find an alternative option for preventive dentistry by examining both in vitro and clinically, the antibacterial, antihalitosis, and anti-inflammatory effects of folic acid (FA) in dogs with periodontal disease. The antibacterial and antihalitosis responses of FA were evaluated in vitro using Porphyromonas gulae, a bacterium that plays a significant role in the development of periodontal disease in dogs. Anti-inflammatory responses, such as secretion of IL-1β, IL-6, and IL-8 induced by P. gulae infection in human gingival epithelium have been studied. This study used dogs with P. gulae-associated periodontal diseases and was conducted by providing a dental chew containing 0.13% FA for 28 days. The viability and halitosis production (hydrogen sulfide and methyl mercaptan) of P. gulae was significantly inhibited by FA in a dose and time-dependent manner. IL-1β, IL-6, and IL-8 secretion were also significantly suppressed by FA treatment in a dose-dependent manner. In vitro bactericidal, antihalitosis, and anti-inflammatory effects of FA were confirmed in dogs with P. gulae-associated periodontal disease. One month of oral treatment with 0.13% FA-containing dental chews significantly reduced halitosis as well as P. gulae activity. This study suggests that oral treatment with FA can be a preventive option for periodontal disease in dogs as well as humans.

Porphyromonas gingivalis, a bridge between oral health and immune evasion in gastric cancer

Porphyromonas gingivalis (P. gingivalis) is a gram-negative oral pathogen associated with chronic periodontitis. Previous studies have linked poor oral health and periodontitis with oral cancer. Severe cases of periodontal disease can result in advanced periodontitis, leading to tissue degradation, tooth loss, and may also correlate with higher gastric cancer (GC) risk. In fact, tooth loss is associated with an elevated risk of cancer. However, the clinical evidence for this association remains inconclusive. Periodontitis is also characterized by chronic inflammation and upregulation of members of the Programmed Death 1/PD1 Ligand 1 (PD1/PDL1) axis that leads to an immunosuppressive state. Given that chronic inflammation and immunosuppression are conditions that facilitate cancer progression and carcinogenesis, we hypothesize that oral P. gingivalis and/or its virulence factors serve as a mechanistic link between oral health and gastric carcinogenesis/GC progression. We also discuss the potential impact of P. gingivalis' virulence factors (gingipains, lipopolysaccharide (LPS), and fimbriae) on inflammation and the response to immune checkpoint inhibitors in GC which are part of the current standard of care for advanced stage patients.

Evaluation of the antibacterial effect of Epigallocatechin gallate on the major pathogens of canine periodontal disease and therapeutic effects on periodontal disease mice

Background

Periodontal disease (PD) is a prevalent oral affliction in canines, with limited therapeutic options available. The potential transmission of oral bacteria from canines to humans through inter-species contact poses a risk of zoonotic infection. Epigallocatechin gallate (EGCG), the principal catechin in green tea polyphenols, exhibits antibacterial properties effective against human PD. Given the clinical parallels between canine and human PD, this study explores the feasibility of employing EGCG as a therapeutic agent for canine PD.

Methods and results

Initially, a survey and statistical analysis of bacterial infection data related to canine PD in China were conducted. Subsequently, the primary pathogenic bacteria of canine PD were isolated and cultivated, and the in vitro antibacterial efficacy of EGCG was assessed. Furthermore, verify the therapeutic effect of EGCG on a mouse PD model in vivo. The high-throughput 16S rRNA gene sequencing identified Porphyromonas, Fusobacterium, Treponema, Moraxella, and Capnocytophaga as the genera that distinguishing PD from healthy canines' gingival crevicular fluid (GCF) samples in China. The anaerobic culture and drug susceptibility testing isolated a total of 92 clinical strains, representing 22 species, from 72 canine GCF samples, including Porphyromonas gulae, Prevotella intermedia, Porphyromonas macacae, etc. The minimum inhibitory concentration (MIC) ranging of EGCG was from 0.019 to 1.25 mg/mL. Following a 7 days oral mucosal administration of medium-dose EGCG (0.625 mg/mL), the abundance of periodontal microorganisms in PD mice significantly decreased. This intervention ameliorated alveolar bone loss, reducing the average cementoenamel junction to the alveolar bone crest (CEJ-ABC) distance from 0.306 mm ± 0.050 mm to 0.161 mm ± 0.026 mm. Additionally, EGCG (0.3125 mg/mL) markedly down-regulated the expression of inflammatory factor IL-6 in the serum of PD mice.

Conclusion

Our research demonstrates the significant antibacterial effects of EGCG against the prevalent bacterium P. gulae in canine PD. Moreover, EGCG exhibits anti-inflammatory properties and proves effective in addressing bone loss in a PD mouse model. These findings collectively suggest the therapeutic potential of EGCG in the treatment of canine PD. The outcomes of this study contribute valuable data, laying the foundation for further exploration and screening of alternative antibiotic drugs to advance the management of canine PD.

Regulation of toll-like receptor (TLR) signaling pathways in atherosclerosis: from mechanisms to targeted therapeutics

Atherosclerosis, one of the life-threatening cardiovascular diseases (CVDs), has been demonstrated to be a chronic inflammatory disease, and inflammatory and immune processes are involved in the origin and development of the disease. Toll-like receptors (TLRs), a class of pattern recognition receptors that trigger innate immune responses by identifying pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), regulate numerous acute and chronic inflammatory diseases. Recent studies reveal that TLRs have a vital role in the occurrence and development of atherosclerosis, including the initiation of endothelial dysfunction, interaction of various immune cells, and activation of a number of other inflammatory pathways. We herein summarize some other inflammatory signaling pathways, protein molecules, and cellular responses associated with TLRs, such as NLRP3, Nrf2, PCSK9, autophagy, pyroptosis and necroptosis, which are also involved in the development of AS. Targeting TLRs and their regulated inflammatory events could be a promising new strategy for the treatment of atherosclerotic CVDs. Novel drugs that exert therapeutic effects on AS through TLRs and their related pathways are increasingly being developed. In this article, we comprehensively review the current knowledge of TLR signaling pathways in atherosclerosis and actively seek potential therapeutic strategies using TLRs as a breakthrough point in the prevention and therapy of atherosclerosis.

Green tea catechins inhibit Porphyromonas gulae LPS-induced inflammatory responses in human gingival epithelial cells: Running title

OBJECTIVES

To determine the anti-inflammatory effects of green tea catechins in immortalized human gingival epithelial cells (Ca9-22) stimulated with Porphyromonas gulae lipopolysaccharide (LPS).

METHODS

Ca9-22 cells were incubated with P. gulae LPS (10 μg/ml) with or without green tea catechins, epigallocatechin-3-gallate (EGCg), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epicatechin (EC) (each at 50 μM), for 6 or 24 hours. Real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay were used to determine the induction of cyclooxygenase 2 (COX2), tumor necrosis factor alpha (TNF-ɑ), interleukin 6 (IL-6), and IL-8. Furthermore, the expression of toll-like receptors (TLRs) 2 and 4 was examined using real-time PCR and western blotting analysis, and phosphorylation of the p38 and ERK1/2 was examined using western blotting analysis.

RESULTS

At the mRNA and protein levels, EGCg, EGC, ECG, and EC were found to significantly inhibit COX2, TNF-ɑ, IL-6, and IL-8. Furthermore, the levels of ERK1/2 and p38 phosphorylation induced by P. gulae LPS were decreased following the addition of each of the catechins, as well as TLR2 and 4 mRNA and protein.

CONCLUSIONS

These findings indicate that green tea catechins are potent inhibitors of inflammatory responses induced by P. gulae LPS, and may also be useful for prevention and/or attenuation of periodontitis.

Periodontopathic Microbiota and Atherosclerosis: Roles of TLR-Mediated Inflammation Response

Atherosclerosis is a chronic inflammatory disease with a high prevalence worldwide, contributing to a series of adverse cardiovascular and cerebrovascular diseases. Periodontal disease induced by pathogenic periodontal microbiota has been well established as an independent factor of atherosclerosis. Periodontal microorganisms have been detected in atherosclerotic plaques. The high-risk microbiota dwelling in the subgingival pocket can stimulate local and systematic host immune responses and inflammatory cascade reactions through various signaling pathways, resulting in the development and progression of atherosclerosis. One often-discussed pathway is the Toll-like receptor-nuclear factor-κB (TLR-NF-κB) signaling pathway that plays a central role in the transduction of inflammatory mediators and the release of proinflammatory cytokines. This narrative review is aimed at summarizing and updating the latest literature on the association between periodontopathic microbiota and atherosclerosis and providing possible therapeutic ideas for clinicians regarding atherosclerosis prevention and treatment.

Efficacy of FimA antibody and clindamycin in silkworm larvae stimulated with Porphyromonas gulae

Objective: Porphyromonas gulae, a major periodontal pathogen in animals, possesses fimbriae that have been classified into three genotypes (A, B, C) based on the diversity of fimA genes encoding fimbrillin protein (FimA). P. gulae strains with type C fimbriae were previously shown to be more virulent than other types. In this study, we further examined the host toxicity mediated by P. gulae fimbriae by constructing recombinant FimA (rFimA) expression vectors for each genotype and raised antibodies to the purified proteins.

Methods and Results: All larvae died within 204 h following infection with P. gulae type C at the low-dose infection, whereas type A and B did not. Among fimA types, the survival rates of the larvae injected with rFimA type C were remarkably decreased, while the survival rates of the larvae injected with rFimA type A and type B were greater than 50%. Clindamycin treatment inhibited the growth of type C strains in a dose-dependent manner, resulting in an increased rate of silkworm survival. Finally, type C rFimA-specific antiserum prolonged the survival of silkworm larvae stimulated by infection with P. gulae type C strain or injection of rFimA type C protein.

Conclusion: These results suggested that type C fimbriae have high potential for enhancement of bacterial pathogenesis, and that both clindamycin and anti-type C rFimA-specific antibodies are potent inhibitors of type C fimbriae-induced toxicity. This is the first report to establish a silkworm infection model using P. gulae for toxicity assessment.