Macrophages: A communication network linking Porphyromonas gingivalis infection and associated systemic diseases

Role of macrophage polarization in periodontitis promoting atherosclerosis

Periodontitis is a chronic inflammatory destructive disease occurring in periodontal supporting tissues. Atherosclerosis(AS) is one of the most common cardiovascular diseases. Periodontitis can promote the development and progression of AS. Macrophage polarization is closely related to the development and progression of the above two diseases, respectively. The purpose of this animal study was to evaluate the effect of periodontitis on aortic lesions in atherosclerotic mice and the role of macrophage polarization in this process. 45 ApoE-/-male mice were randomly divided into three groups: control (NC), atherosclerosis (AS), and atherosclerosis with periodontitis (AS + PD). Micro CT, serological testing and pathological testing(hematoxylin-eosin staining, oil red O staining and Masson staining) were used for Evaluate the modeling situation. Immunohistochemistry(IHC) and immunofluorescence(IF) were performed to evaluate macrophage content and macrophage polarization in plaques. Cytokines associated with macrophage polarization were analyzed using quantitative real-time polymerase chain reaction(qRT-PCR) and enzyme-linked immunosorbent assay(Elisa). The expression of macrophages in plaques was sequentially elevated in the NC, AS, and AS + PD groups(P < 0.001). The expression of M1 and M1-related cytokines showed the same trend(P < 0.05). The expression of M2 and M2-related cytokines showed the opposite trend(P < 0.05). The rate of M1/M2 showed that AS + PD > AS > NC. Our preliminary data support that experimental periodontitis can increase the content of macrophage in aortic plaques to exacerbate AS. Meanwhile, experimental periodontitis can increase M1 macrophages, and decrease M2 macrophages, increasing M1/M2 in the plaque.

Unravelling the intricacies of Porphyromonas gingivalis: virulence factors, lifecycle dynamics and phytochemical interventions for periodontal disease management

Porphyromonas gingivalis is a gram-negative anaerobic bacterium recognized for its pivotal role in the pathogenesis of periodontal diseases. This review covers an overview of the virulence factors and lifecycle stages of P. gingivalis, with a specific focus on attachment and colonization, biofilm formation, growth and multiplication, dormancy survival and dissemination. Additionally, we explore the significance of inter-bacterial cross-feeding within biofilms. Furthermore, we discuss potential phytochemical-based strategies to target P. gingivalis, including the use of curcumin, apigenin, quercetin and resveratrol. Understanding the virulence factors and lifecycle stages of P. gingivalis, along with the promising phytochemical-based interventions, holds promise for advancing strategies in periodontal disease management and oral health promotion.

Periodontal pathogens and cancer development

Increasing evidence suggests a significant association between periodontal disease and the occurrence of various cancers. The carcinogenic potential of several periodontal pathogens has been substantiated in vitro and in vivo. This review provides a comprehensive overview of the diverse mechanisms employed by different periodontal pathogens in the development of cancer. These mechanisms induce chronic inflammation, inhibit the host's immune system, activate cell invasion and proliferation, possess anti-apoptotic activity, and produce carcinogenic substances. Elucidating these mechanisms might provide new insights for developing novel approaches for tumor prevention, therapeutic purposes, and survival improvement.

Macrophage membrane-coated nanoparticles for the treatment of infectious diseases

Infectious diseases severely threaten human health, and traditional treatment techniques face multiple limitations. As an important component of immune cells, macrophages display unique biological properties, such as biocompatibility, immunocompatibility, targeting specificity, and immunoregulatory activity, and play a critical role in protecting the body against infections. The macrophage membrane-coated nanoparticles not only maintain the functions of the inner nanoparticles but also inherit the characteristics of macrophages, making them excellent tools for improving drug delivery and therapeutic implications in infectious diseases (IDs). In this review, we describe the characteristics and functions of macrophage membrane-coated nanoparticles and their advantages and challenges in ID therapy. We first summarize the pathological features of IDs, providing insight into how to fight them. Next, we focus on the classification, characteristics, and preparation of macrophage membrane-coated nanoparticles. Finally, we comprehensively describe the progress of macrophage membrane-coated nanoparticles in combating IDs, including drug delivery, inhibition and killing of pathogens, and immune modulation. At the end of this review, a look forward to the challenges of this aspect is presented.

Cystatin C: immunoregulation role in macrophages infected with Porphyromonas gingivalis

Background

Periodontitis is a chronic infectious disease, characterized by an exacerbated inflammatory response and a progressive loss of the supporting tissues of the teeth. Porphyromonas gingivalis is a key etiologic agent in periodontitis. Cystatin C is an antimicrobial salivary peptide that inhibits the growth of P. gingivalis. This study aimed to evaluate the antimicrobial activity of this peptide and its effect on cytokine production, nitric oxide (NO) release, reactive oxygen species (ROS) production, and programmed cell death in human macrophages infected with P. gingivalis.

Methods

Monocyte-derived macrophages generated from peripheral blood were infected with P. gingivalis (MOI 1:10) and stimulated with cystatin C (2.75 µg/ml) for 24 h. The intracellular localization of P. gingivalis and cystatin C was determined by immunofluorescence and transmission electron microscopy (TEM). The intracellular antimicrobial activity of cystatin C in macrophages was assessed by counting Colony Forming Units (CFU). ELISA assay was performed to assess inflammatory (TNFα, IL-1β) and anti-inflammatory (IL-10) cytokines. The production of nitrites and ROS was analyzed by Griess reaction and incubation with 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), respectively. Programmed cell death was assessed with the TUNEL assay, Annexin-V, and caspase activity was also determined.

Results

Our results showed that cystatin C inhibits the extracellular growth of P. gingivalis. In addition, this peptide is internalized in the infected macrophage, decreases the intracellular bacterial load, and reduces the production of inflammatory cytokines and NO. Interestingly, peptide treatment increased ROS production and substantially decreased bacterial-induced macrophage apoptosis.

Conclusions

Cystatin C has antimicrobial and immuno-regulatory activity in macrophages infected with P. gingivalis. These findings highlight the importance of understanding the properties of cystatin C for its possible therapeutic use against oral infections such as periodontitis.

Tim4 deficiency reduces CD301b+ macrophage and aggravates periodontitis bone loss

Periodontitis is a common chronic inflammatory disease that causes the periodontal bone destruction and may ultimately result in tooth loss. With the progression of periodontitis, the osteoimmunology microenvironment in periodontitis is damaged and leads to the formation of pathological alveolar bone resorption. CD301b+ macrophages are specific to the osteoimmunology microenvironment, and are emerging as vital booster for conducting bone regeneration. However, the key upstream targets of CD301b+ macrophages and their potential mechanism in periodontitis remain elusive. In this study, we concentrated on the role of Tim4, a latent upstream regulator of CD301b+ macrophages. We first demonstrated that the transcription level of Timd4 (gene name of Tim4) in CD301b+ macrophages was significantly upregulated compared to CD301b- macrophages via high-throughput RNA sequencing. Moreover, several Tim4-related functions such as apoptotic cell clearance, phagocytosis and engulfment were positively regulated by CD301b+ macrophages. The single-cell RNA sequencing analysis subsequently discovered that Cd301b and Timd4 were specifically co-expressed in macrophages. The following flow cytometric analysis indicated that Tim4 positive expression rates in total macrophages shared highly synchronized dynamic changes with the proportions of CD301b+ macrophages as periodontitis progressed. Furthermore, the deficiency of Tim4 in mice decreased CD301b+ macrophages and eventually magnified alveolar bone resorption in periodontitis. Additionally, Tim4 controlled the p38 MAPK signaling pathway to ultimately mediate CD301b+ macrophages phenotype. In a word, Tim4 might regulate CD301b+ macrophages through p38 MAPK signaling pathway in periodontitis, which provided new insights into periodontitis immunoregulation as well as help to develop innovative therapeutic targets and treatment strategies for periodontitis.

[Periodontitis : An underestimated risk of cardiovascular diseases]

Epidemiological studies have identified periodontitis as a contributing factor to cardiovascular risk. Periodontitis is a chronic inflammatory disease that affects the tissues supporting the teeth. Although the nature of the association between periodontitis and cardiovascular disease (CVD) remains to be defined, the low-grade systemic inflammation and chronic bacteremia associated with periodontitis appear to be involved in the development of atherosclerosis and associated cardiovascular pathologies. Periodontal treatment has been shown to improve cardiovascular health parameters. A bidirectional preventive approach, involving the management of both periodontitis and cardiovascular risk factors, could lead to a reduction in morbidity and mortality related to cardiovascular disease.

Ebselen Optimized the Therapeutic Effects of Silver Nanoparticles for Periodontal Treatment

Objective

Silver nanoparticles (AgNPs) possess excellent antibacterial effects on periodontal pathogens, but their clinical application is limited mainly due to their cytotoxicity through inducing oxidative stress in human cells. Ebselen disrupts the reactive oxygen species (ROS) scavenging in bacteria and relieves oxidative stress in mammalian cells. This study aimed to assess the antibacterial and anti-inflammatory effects of AgNPs and ebselen as well as the protective effect of ebselen, to further provide the theoretical basis for their future application in periodontal treatment.

Methods

The antibacterial and anti-biofilm effects of the synthesized AgNPs combined with ebselen were assessed on Porphyromonas gingivalis (P. gingivalis), Streptococcus gordonii (S. gordonii), and Fusobacterium nucleatum (F. nucleatum) in planktonic condition and as biofilms. In addition, the intracellular bactericidal efficiency of AgNPs and ebselen was evaluated in P. gingivalis-infected human gingival fibroblasts (HGFs). The cytotoxicity, intracellular ROS levels, and potential antioxidative enzymes were detected in HGFs treated with AgNPs and ebselen. Further, the anti-inflammatory effects were evaluated by in vitro and in vivo experiments.

Results

The combination of AgNPs and ebselen showed excellent antibacterial effects against planktonic P. gingivalis and F. nucleatum and synergistic antibiofilm effects on all mono- and multi-species biofilms. In addition, ebselen significantly enhanced the intracellular bactericidal efficiency of AgNPs. Furthermore, ebselen combined with up to 20 μg/mL AgNPs showed no obvious cytotoxicity to HGFs. Evidently, ebselen alleviated the AgNPs-induced ROS by increasing the levels of glutathione and superoxide dismutase 2. Moreover, AgNPs and ebselen together declined the release of P. gingivalis-stimulated inflammatory cytokines both in vitro and in vivo, and reduced alveolar bone resorption effectively.

Conclusion

AgNPs combined with ebselen would be an effective adjuvant for periodontal treatment owing to their synergistic antibacterial and anti-inflammatory effects.

A biomimetic phototherapeutic nanoagent based on bacterial double-layered membrane vesicles for comprehensive treatment of oral squamous cell carcinoma

As one of the most common malignancies, oral squamous cell carcinoma (OSCC) with high rates of invasiveness and metastasis threatens people's health worldwide, while traditional therapeutic approaches have not met the requirement of its cure. Phototherapies including photothermal therapy (PTT) and photodynamic therapy (PDT) have shown great potential for OSCC treatment due to their noninvasiveness or minimal invasiveness, high selectivity and little tolerance. However, PTT or PDT alone makes it difficult to eradicate OSCC and prevent its metastasis and recurrence. Here, double-layered membrane vesicles (DMVs) were extracted from attenuated Porphyromonas gingivalis, one of the most common pathogens inside the oral region, and served as an immune adjuvant to develop a biomimetic phototherapeutic nanoagent named PBAE/IR780@DMV for OSCC treatment via combining dual PTT/PDT and robust antitumor immunity. To obtain PBAE/IR780@DMV, poly(β-amino) ester (PBAE) was used as a carrier material to prepare the nanoparticles for loading IR780, a widely known photosensitizer possessing both PTT and PDT capabilities, followed by surface wrapping with DMVs. Upon 808 nm laser irradiation, PBAE/IR780@DMV exerted strong antitumor effects against OSCC both in vitro and in vivo, via combining PTT/PDT and specific immune responses triggered by tumor-associated antigens and DMVs. Altogether, this study provides a promising biomimetic phototherapeutic nanoagent for comprehensive treatment of OSCC.

The oral-gut-circulatory axis: from homeostasis to colon cancer

The human microbiota is widely recognized as providing crucial health benefits to its host, specifically by modulating immune homeostasis. Microbial imbalance, known as dysbiosis, is linked to several conditions in the body. The oral cavity and gut host the two largest microbial communities playing a major role in microbial-associated diseases. While the oral-gut axis has been previously explored, our review uniquely highlights the significance of incorporating the circulatory system into this axis. The interaction between immune cells, inflammatory factors, circulating bacteria, and microbial metabolites influences the homeostasis of both the oral and gut microbiota in a bidirectional manner. In this comprehensive review, we aim to describe the bacterial components of the oral-gut-circulatory axis in both health and disease, with a specific focus on colon cancer.

Alterations in macrophage polarization play a key role in control and development of periodontal diseases

Periodontitis is a chronic inflammatory disease driven by complex interplays between a dysbiotic oral microbiome and a dysregulated host inflammatory response that results in the destruction of the tooth-supporting apparatus. Among the inflammatory cells involved in the pathogenesis of periodontitis, macrophages are recruited early on to sites of periodontal infection. These cells can polarize in different phenotypes that mediate the initiation and resolution of inflammatory responses, as well as in tissue healing. Macrophage phenotypic plasticity is thought to play a critical role in the induction and resolution of inflammation and may be compromised in patients with chronic inflammatory diseases. Here, we reviewed the role of macrophage polarization in periodontal disease and therapy.

Immune-related signature of periodontitis and Alzheimer's disease linkage

Background: Periodontits (PD) and Alzheimer's disease (AD) are both associated with ageing and clinical studies increasingly evidence their association. However, specific mechanisms underlying this association remain undeciphered, and immune-related processes are purported to play a signifcant role. The accrual of publicly available transcriptomic datasets permits secondary analysis and the application of data-mining and bioinformatic tools for biological discovery. Aim: The present study aimed to leverage publicly available transcriptomic datasets and databases, and apply a series of bioinformatic analysis to identify a robust signature of immune-related signature of PD and AD linkage. Methods: We downloaded gene-expresssion data pertaining PD and AD and identified crosstalk genes. We constructed a protein-protein network analysis, applied immune cell enrichment analysis, and predicted crosstalk immune-related genes and infiltrating immune cells. Next, we applied consisent cluster analysis and performed immune cell bias analysis, followed by LASSO regression to select biomarker immune-related genes. Results: The results showed a 3 gene set comprising of DUSP14, F13A1 and SELE as a robust immune-related signature. Macrophages M2 and NKT, B-cells, CD4+ memory T-cells and CD8+ naive T-cells emerged as key immune cells linking PD with AD. Conclusion: Candidate immune-related biomarker genes and immune cells central to the assocation of PD with AD were identified, and merit investigation in experimental and clinical research.

Oral pathogen aggravates atherosclerosis by inducing smooth muscle cell apoptosis and repressing macrophage efferocytosis

Periodontitis imparting the increased risk of atherosclerotic cardiovascular diseases is partially due to the immune subversion of the oral pathogen, particularly the Porphyromonas gingivalis (P. gingivalis), by inducing apoptosis. However, it remains obscure whether accumulated apoptotic cells in P. gingivalis-accelerated plaque formation are associated with impaired macrophage clearance. Here, we show that smooth muscle cells (SMCs) have a greater susceptibility to P. gingivalis-induced apoptosis than endothelial cells through TLR2 pathway activation. Meanwhile, large amounts of miR-143/145 in P.gingivalis-infected SMCs are extracellularly released and captured by macrophages. Then, these miR-143/145 are translocated into the nucleus to promote Siglec-G transcription, which represses macrophage efferocytosis. By constructing three genetic mouse models, we further confirm the in vivo roles of TLR2 and miR-143/145 in P. gingivalis-accelerated atherosclerosis. Therapeutically, we develop P.gingivalis-pretreated macrophage membranes to coat metronidazole and anti-Siglec-G antibodies for treating atherosclerosis and periodontitis simultaneously. Our findings extend the knowledge of the mechanism and therapeutic strategy in oral pathogen-associated systemic diseases.

Porphyromonas gingivalis regulates atherosclerosis through an immune pathway

Atherosclerosis (AS) is a chronic inflammatory disease, involving a pathological process of endothelial dysfunction, lipid deposition, plaque rupture, and arterial occlusion, and is one of the leading causes of death in the world population. The progression of AS is closely associated with several inflammatory diseases, among which periodontitis has been shown to increase the risk of AS. Porphyromonas gingivalis (P. gingivalis), presenting in large numbers in subgingival plaque biofilms, is the “dominant flora” in periodontitis, and its multiple virulence factors are important in stimulating host immunity. Therefore, it is significant to elucidate the potential mechanism and association between P. gingivalis and AS to prevent and treat AS. By summarizing the existing studies, we found that P. gingivalis promotes the progression of AS through multiple immune pathways. P. gingivalis can escape host immune clearance and, in various forms, circulate with blood and lymph and colonize arterial vessel walls, directly inducing local inflammation in blood vessels. It also induces the production of systemic inflammatory mediators and autoimmune antibodies, disrupts the serum lipid profile, and thus promotes the progression of AS. In this paper, we summarize the recent evidence (including clinical studies and animal studies) on the correlation between P. gingivalis and AS, and describe the specific immune mechanisms by which P. gingivalis promotes AS progression from three aspects (immune escape, blood circulation, and lymphatic circulation), providing new insights into the prevention and treatment of AS by suppressing periodontal pathogenic bacteria.