Immunotherapy with regulatory T and B cells in periodontitis

Regulatory T Cells promote osteogenic differentiation of periodontal ligament stem cells through the Jagged1-Notch2 signaling Axis

OBJECTIVES

This study aimed to elucidate the role of regulatory T cells (Tregs) in promoting the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) and to investigate the underlying mechanisms involving Notch signaling.

METHOD

Tregs were isolated via fluorescence-activated cell sorting (FACS) and co-cultured with PDLSCs. Osteogenic differentiation was assessed through in vitro assays and in vivo transplantation experiments. Gene expression profiles were quantified using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot analysis. A murine periodontitis model was used to validated therapeutic outcomes, with bone remodeling quantified by micro-CT and histology (H&E, Masson's staining). Immunophenotypic analysis of Jagged1 expression in Tregs and Notch2 receptor localization in PDLSCs were performed using flow cytometry and immunofluorescence microscopy, respectively. The role of immobilized Jagged1 in osteogenic differentiation was further evaluated, while Notch pathway inhibition was achieved via γ-secretase inhibitor DAPT in vitro.

RESULTS

Elevated levels of Th17 cells and Tregs were observed in peripheral blood samples from periodontitis patients, with a significantly increased Th17/Treg ratio (p < 0.01). In vitro, co-culturing Tregs with PDLSCs significantly enhanced PDLSC osteogenesis, as evidenced by increased ALP activity (p < 0.01), elevated expression of osteogenesis-related genes (Runx2 and Osterix; p < 0.01), and enhanced mineralization (Alizarin Red staining) (p < 0.01). In vivo, intravenous infusion of Tregs into a periodontitis mouse model reduced periodontal damage and promoted bone regeneration, as demonstrated by reduced CEJ-ABC distance and increased BV/TV ratio (p < 0.01). Mechanistically, Tregs expressed the Notch ligand Jagged1 and upregulated Notch2 receptor expression in PDLSCs, indicating activation of the Notch signaling pathway. Jagged1 promoted osteogenic differentiation of PDLSCs in a dose- and time-dependent manner. Inhibition of Notch signaling using DAPT reduced Tregs-mediated enhancement of PDLSC osteogenesis (p < 0.05).

CONCLUSION

These findings suggest that Tregs promote PDLSC osteogenic differentiation via Jagged1-Notch2 signaling, highlighting the therapeutic potential of modulating Tregs and Notch signaling for periodontal regeneration and bone tissue engineering.

CLINICAL SIGNIFICANCE

This study provides new insights into the complex interplay between immune modulation and stem cell differentiation, laying the foundation for potential Tregs-based therapeutic strategies for periodontal and bone tissue regeneration.

Therapeutic efficacy of rituximab combined with cyclosporin A on B-cell dysregulation in chronic graft-versus-host disease

OBJECTIVE

Chronic graft-versus-host disease (cGVHD) is a significant complication following allogenic hematopoietic stem cell transplantation, often necessitating therapeutic interventions such as rituximab (RTX) and cyclosporin A (CsA). This study aims to elucidate the mechanisms by which RTX and CsA jointly address B-cell dysregulation in cGVHD, providing a theoretical foundation and scientific rationale for the treatment and prognostic evaluation of this condition.

METHODS

A total of 30 cGVHD mouse models were established by subjecting recipient mice to total body irradiation followed by injection of a mixed suspension of bone marrow cells and splenocytes from donor mice. From Day 2 to Day 29 post-model establishment, the mice received subcutaneous administration of RTX and CsA. Throughout the study, body weight, clinical cGVHD scores, and survival rates were monitored. Blood samples were collected via the orbital venous plexus. Serum levels of B-cell activating factor (BAFF) and pro-inflammatory factors were measured using enzyme-linked immunosorbent assay (ELISA), and the ratio of regulatory B cells (Bregs) in the blood sample was assessed via flow cytometry.

RESULTS

Mice with cGVHD exhibited a 14.5% decrease in body weight, elevated clinical scores, and more severe symptoms compared to the control group. Notably, all mice in both the cGVHD and control groups survived until the conclusion of the study. Induction of cGVHD resulted in B-cell dysregulation, evidenced by elevated serum BAFF levels and a decreased proportion of Bregs. However, treatment with RTX combined with CsA ameliorated B-cell dysregulation and significantly reduced serum levels of pro-inflammatory factors in cGVHD mice, with decreases of 39.78% in TNF-α and 37.89% in IL-6.

CONCLUSION

The combination of RTX and CsA effectively mitigates B-cell dysregulation in cGVHD, thereby reducing the severity and progression of the disease.

Peripheral blood immune cell levels differ with the stage and grade of periodontitis in systemically healthy individuals

OBJECTIVES

To explore the level of peripheral blood immune cells in patients with different stages and grades of periodontitis.

MATERIALS AND METHODS

A total of 229 periodontitis patients and 36 periodontally healthy patients were included in this cross-sectional study. Individuals with systemic diseases were excluded. A periodontal examination and a complete blood cell examination were performed. The percentages of T and B cells and their subsets were analyzed via flow cytometry. Covariance and logistic regression analyses were conducted, and receiver operating characteristic curve analysis was used to assess the predictive ability of the indicators.

RESULTS

The white blood cell (WBC) count, absolute neutrophil count (ANC), neutrophil percentage (NEU%) and neutrophil-to-lymphocyte ratio (NLR) were greater, but the lymphocyte percentage (LYM%) was lower in the periodontitis group than in the healthy control group. Patients with severe periodontitis (Stage III and IV) presented higher WBC, ANC, NEU% and NLR than those with mild and moderate periodontitis (Stage I and II) did. Area under curve (AUC) of the ANC, NEU% and NLR for the prediction of Stage III/IV periodontitis were 0.750, 0.771, and 0.774, respectively. Compared with Grade A or B periodontitis patients, Grade C periodontitis patients had a significantly lower absolute lymphocyte count (ALC) and LYM% but higher NEU% and NLR in Grade C periodontitis. The AUC of the NLR, LYM% and NEU% for predicting Grade C periodontitis were 0.797, 0.799, and 0.793, respectively. In lymphocytes, the proportions of T and B cells were lower in Grade C periodontitis patients than in Grade A or B group. Similarly, immune regulatory cells, including B10 and Treg cells, also decreased. Conversely, the Th17/Treg ratio was greater. Moreover, the Th17/Treg ratio was most strongly correlated with Grade C periodontitis (r = 0.87), followed by Treg cells(r = -0.70) and B10 cells(r = -0.38).

CONCLUSIONS

ANC, NEU%, NLR and LYM% are closely correlated with periodontitis. ANC, NEU%, and NLR may serve as potential markers for Stage III/IV periodontitis. LYM%, NEU%, and NLR may serve as potential markers for Grade C periodontitis. An increase in the Th17/Treg ratio is a high-risk factor for Grade C periodontitis.

CLINICAL RELEVANCE

Peripheral immune cell levels vary with the stage and grade of periodontitis and can be used to distinguish the grade and stage of periodontitis.

Smart biomaterial gels for periodontal therapy: A novel approach

Periodontitis, a chronic inflammatory condition of the oral cavity, is characterized by the progressive destruction of the supporting structures of the teeth. The pathogenic effects of periodontopathogens extend beyond the local periodontal environment, contributing to systemic health complications, thereby underscoring the need for effective therapeutic strategies. Current standard treatments, which involve mechanical debridement coupled with systemic anti-inflammatory and antibiotic therapies, are often associated with limited efficacy, adverse effects, and the emergence of antibiotic resistance. Recent advancements in localized drug delivery systems present an innovative alternative, offering site-specific targeting with sustained therapeutic action. Smart drug delivery platforms, designed to respond to the unique microenvironment of periodontal pockets, undergo physicochemical transformations such as gelation or controlled drug release, enhancing treatment efficacy. This review comprehensively explores the etiological and prognostic factors of periodontitis, critical diagnostic biomarkers, and an in-depth analysis of stimuli-responsive biomacromolecule-based gels. These systems are evaluated for their structural properties, biological compatibility, and therapeutic potential while addressing their limitations and barriers to clinical translation. By integrating insights into the interplay between material properties and biological performance, this review highlights the future role of these advanced delivery systems in overcoming challenges in periodontal healthcare. Such approaches aim to bridge the gap between bench-side innovation and bedside application, offering the transformative potential to enhance therapeutic outcomes and improve patient quality of life in managing periodontal diseases.

Application of Nanomaterials Targeting Immune Cells in the Treatment of Chronic Inflammation

Chronic inflammation is a common characteristic of all kinds of diseases, including autoimmune diseases, metabolic diseases, and tumors. It is distinguished by the presence of low concentrations of inflammatory factors stimulating the body for an extended period, resulting in a persistent state of infection. This condition is manifested by the aggregation and infiltration of mononuclear cells, lymphocytes, and other immune cells, leading to tissue hyperplasia and lesions. Although various anti-inflammatory medications, including glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs), have shown strong therapeutic effects, they lack specificity and targeting ability, and require high dosages, which can lead to severe adverse reactions. Nanoparticle drug delivery mechanisms possess the capacity to minimize the effect on healthy cells or tissues due to their targeting capabilities and sustained drug release properties. However, most nanosystems can only target the inflammatory sites rather than specific types of immune cells, leaving room for further improvement in the therapeutic effects of nanomaterials. This article reviews the current research progress on the role of diverse immune cells in inflammation, focusing on the functions of neutrophils and macrophages during inflammation. It provides an overview of the domestic and international applications of nanomaterials in targeted therapy for inflammation, aiming to establish a conceptual foundation for the utilization of nanomaterials targeting immune cells in the treatment of chronic inflammation and offer new perspectives for the avoidance and management of inflammation.

MMP-12 and Periodontitis: Unraveling the Molecular Pathways of Periodontal Tissue Destruction

Periodontal disease is a common disorder affecting a wide range of people and has a high prevalence globally. Periodontitis comprises a series of inflammatory conditions affecting periodontal support tissue, which could ultimately lead to tooth loss and reduce life quality and add to the financial burden of society. Matrix metalloproteinase-12 (MMP-12) is an elastase that is produced mostly by macrophages and could degrade a wide spectrum of extracellular matrix (ECM) and also contribute to several systematic pathological conditions. Recently, researchers have reported higher expression of MMP-12 in chronic periodontitis patients. However, there are few reports on the role of MMP-12 in periodontitis pathogenicity, and the interaction between MMP-12, periodontal pathogens, and periodontal tissues remains unclear. In this review, we introduce the potentially unique role of MMP-12 in the context of periodontal inflammation earlier, summarize the possible effects of MMP-12 on the pathological process of periodontitis and the interaction of host response under the challenge of various inflammatory factors, and provide possible diagnostic and therapeutic strategies targeting MMP-12 for the management of periodontitis. Future research and policies should focus on and implement effective chairside testing methods to reduce the prevalence of periodontal diseases.

Pharmacology and therapeutic potential of agarwood and agarwood tree leaves in periodontitis

The main bioactive components of agarwood, derived from Aquilaria sinensis, include sesquiterpenes, 2-(2-phenethyl) chromone derivatives, aromatic compounds, and fatty acids, which typically exert anti-inflammatory, antioxidant, immune-modulating, hypoglycemic, and antitumor pharmacological effects in the form of essential oils. Agarwood tree leaves, rich in flavonoids, 2-(2-phenethyl) chromone compounds, and flavonoid compounds, also exhibit significant anti-inflammatory, antioxidant, and immune-modulating effects. These properties are particularly relevant to the treatment of periodontitis, given that inflammatory responses, oxidative stress, and immune dysregulation are key pathological mechanisms of the disease, highlighting the substantial potential of agarwood and agarwood tree leaves in this therapeutic area. However, the low solubility and poor bioavailability of essential oils present challenges that necessitate the development of improved active formulations. In this review, we will introduce the bioactive components, extraction methods, pharmacological actions, and clinical applications of agarwood and agarwood tree leaves, analyzing its prospects for the treatment of periodontitis.

Rational design of multifunctional hydrogels targeting the microenvironment of diabetic periodontitis

Periodontitis is a chronic inflammatory disease and is the primary contributor to adult tooth loss. Diabetes exacerbates periodontitis, accelerates periodontal bone resorption. Thus, effectively managing periodontitis in individuals with diabetes is a long-standing challenge. This review introduces the etiology and pathogenesis of periodontitis, and analyzes the bidirectional relationship between diabetes and periodontitis. In this review, we comprehensively summarize the four pathological microenvironments influenced by diabetic periodontitis: high glucose microenvironment, bacterial infection microenvironment, inflammatory microenvironment, and bone loss microenvironment. The hydrogel design strategies and latest research development tailored to the four microenvironments of diabetic periodontitis are mainly focused on. Finally, the challenges and potential solutions in the treatment of diabetic periodontitis are discussed. We believe this review will be helpful for researchers seeking novel avenues in the treatment of diabetic periodontitis.

Regulatory role of PDK1 via integrated gene analysis of mitochondria-immune response in periodontitis

AIMS

To investigate the association between mitochondrial events and immune response in periodontitis and related regulatory genes.

MAIN METHODS

Gene expression profiles in gingival tissues were retrieved from the Gene Expression Omnibus. Mitochondria-immune response-related differentially expressed genes (MIR-DEGs) between the healthy and periodontitis samples were determined. WGCNA, GO, and KEGG were used to investigate the function and the enriched pathways of MIR-DEGs. The correlation between MIR-DEGs expression and clinical probing pocket depth was analyzed. The MIR-DEGs were further identified and verified in animal samples. A periodontitis model was established in C57BL/6 mice with silk ligation. Micro-computed tomography was used to assess alveolar bone loss. Western blot, quantitative real-time polymerase chain reaction, and immunohistochemical analyses further validated the differential expression of the MIR-DEGs.

KEY FINDINGS

A total of ten MIR-DEGs (CYP24A1, PRDX4, GLDC, PDK1, BCL2A1, CBR3, ARMCX3, BNIP3, IFI27, and UNG) were identified, the expression of which could effectively distinguish patients with periodontitis from the healthy controls. Enhanced immune response was detected in the periodontitis group with that in the healthy controls, especially in B cells. PDK1 was a critical MIR-DEG correlated with B cell immune response and clinical periodontal probing pocket depth. Both animal and clinical periodontal samples presented higher gene and protein expression of PDK1 than the control samples. Additionally, PDK1 colocalized with B cells in both animal and clinical periodontal tissues.

SIGNIFICANCE

Mitochondria participate in the regulation of the immune response in periodontitis. PDK1 may be the key mitochondria-related gene regulating B-cell immune response in periodontitis.

An update on periodontal inflammation and bone loss

Periodontal disease is a chronic inflammatory condition that affects the supporting structures of the teeth, including the periodontal ligament and alveolar bone. Periodontal disease is due to an immune response that stimulates gingivitis and periodontitis, and its systemic consequences. This immune response is triggered by bacteria and may be modulated by environmental conditions such as smoking or systemic disease. Recent advances in single cell RNA-seq (scRNA-seq) and in vivo animal studies have provided new insight into the immune response triggered by bacteria that causes periodontitis and gingivitis. Dysbiosis, which constitutes a change in the bacterial composition of the microbiome, is a key factor in the initiation and progression of periodontitis. The host immune response to dysbiosis involves the activation of various cell types, including keratinocytes, stromal cells, neutrophils, monocytes/macrophages, dendritic cells and several lymphocyte subsets, which release pro-inflammatory cytokines and chemokines. Periodontal disease has been implicated in contributing to the pathogenesis of several systemic conditions, including diabetes, rheumatoid arthritis, cardiovascular disease and Alzheimer's disease. Understanding the complex interplay between the oral microbiome and the host immune response is critical for the development of new therapeutic strategies for the prevention and treatment of periodontitis and its systemic consequences.

Assessment of the Effect on Periodontitis of Antibiotic Therapy and Bacterial Lysate Treatment

Periodontitis is an inflammatory process that starts with soft tissue inflammation caused by the intervention of oral bacteria. By modulating local immunity, it is possible to supplement or replace current therapeutic methods. The aim of this study was to compare the effects of an immunostimulatory treatment with the antibiotherapy usually applied to periodontitis patients. On a model of periodontitis induced in 30 rats (divided into three equal groups) with bacterial strains selected from the human oral microbiome (Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Streptococcus oralis), we administered antibiotics, bacterial lysates and saline for 10 days. Clinically, no significant lesions were observed between the groups, but hematologically, we detected a decrease in lymphocyte and neutrophil counts in both the antibiotic and lysate-treated groups. Immunologically, IL-6 remained elevated compared to the saline group, denoting the body's effort to compensate for bone loss due to bacterial action. Histopathologically, the results show more pronounced oral tissue regeneration in the antibiotic group and a reduced inflammatory reaction in the lysate group. We can conclude that the proposed bacterial lysate has similar effects to antibiotic therapy and can be considered an option in treating periodontitis, thus eliminating the unnecessary use of antibiotics.

TLR2 agonist prevents the progression of periapical lesions in mice by reducing osteoclast activity and regulating the frequency of Tregs

AIM

To evaluate the role of regulatory T lymphocytes (Tregs) in the presence or absence of the synthetic ligand Pam3Cys during the progression of periapical lesion in wild-type (WT) and toll-like receptor 2 knockout (TLR2KO) mice.

METHODOLOGY

A total of 130 C57BL/6 male WT and TLR2KO mice were allocated into control (n = 5) and experimental (periapical lesion induction) (n = 10) groups. In specific groups (WT+Pam3cys and TLR2KO+Pam3cys), the synthetic ligand Pam3cys was administered intraperitoneally every 7 days, according to the experimental period (14, 21 and 42 days). At the end of those periods, the animals were euthanized, and the mandible and the spleen were submitted to histotechnical processing. Mandible histological sections were analysed by haematoxylin and eosin, TRAP histoenzymology and immunohistochemistry (FOXP3, RANK, RANKL and OPG). Spleen sections were analysed by immunohistochemistry (FOXP3).

RESULTS

The inflammatory infiltrate and bone resorption were more intense in the TLR2KO group compared to the WT group. The animals that received the Pam3cys had smaller periapical lesions when compared to the animals that did not receive the ligand (p < .05). TLR2KO animals showed a significant increase in the number of osteoclasts when compared to TLR2KO+Pam3cys group (p < .05). At 21 days, the WT+Pam3cys group had a lower number of osteoclasts when compared to the WT animals (p = .02). FOXP3 expression was more intense in the WT+Pam3cys groups when compared to the WT animals in the 42 days (p = .03). In the spleen analysis, the WT+Pam3cys group also had a higher expression of FOXP3 when compared to the WT animals at 14 and 42 days (p = .02). Concerning RANKL, there was a reduction in staining in the KOTLR2+Pam3cys groups at 21 and 42 days (p = .03) and a higher binding ratio between RANK/RANKL in animals that did not receive the ligand.

CONCLUSION

Administration of the Pam3cys increased the proliferation of Tregs, showed by FOXP3 expression and prevented the progression of the periapical lesion in WT mice. On the other hand, in the TLR2KO animals, Treg expression was lower with larger areas of periapical lesions. Finally, systemic administration of the Pam3cys in KO animals was able to limit the deleterious effects of the absence of the TLR2 receptor.

Regulatory B Cells-Immunopathological and Prognostic Potential in Humans

The aim of the following review is to shed light on the putative role of regulatory B cells (Bregs) in various human diseases and highlight their potential prognostic and therapeutic relevance in humans. Regulatory B cells are a heterogeneous group of B lymphocytes capable of suppressing inflammatory immune reactions. In this way, Bregs contribute to the maintenance of tolerance and immune homeostasis by limiting ongoing immune reactions temporally and spatially. Bregs play an important role in attenuating pathological inflammatory reactions that can be associated with transplant rejection, graft-versus-host disease, autoimmune diseases and allergies but also with infectious, neoplastic and metabolic diseases. Early studies of Bregs identified IL-10 as an important functional molecule, so the IL-10-secreting murine B10 cell is still considered a prototype Breg, and IL-10 has long been central to the search for human Breg equivalents. However, over the past two decades, other molecules that may contribute to the immunosuppressive function of Bregs have been discovered, some of which are only present in human Bregs. This expanded arsenal includes several anti-inflammatory cytokines, such as IL-35 and TGF-β, but also enzymes such as CD39/CD73, granzyme B and IDO as well as cell surface proteins including PD-L1, CD1d and CD25. In summary, the present review illustrates in a concise and comprehensive manner that although human Bregs share common functional immunosuppressive features leading to a prominent role in various human immunpathologies, they are composed of a pool of different B cell types with rather heterogeneous phenotypic and transcriptional properties.

New insights into nanotherapeutics for periodontitis: a triple concerto of antimicrobial activity, immunomodulation and periodontium regeneration

Periodontitis is a chronic inflammatory disease caused by the local microbiome and the host immune response, resulting in periodontal structure damage and even tooth loss. Scaling and root planning combined with antibiotics are the conventional means of nonsurgical treatment of periodontitis, but they are insufficient to fully heal periodontitis due to intractable bacterial attachment and drug resistance. Novel and effective therapeutic options in clinical drug therapy remain scarce. Nanotherapeutics achieve stable cell targeting, oral retention and smart release by great flexibility in changing the chemical composition or physical characteristics of nanoparticles. Meanwhile, the protectiveness and high surface area to volume ratio of nanoparticles enable high drug loading, ensuring a remarkable therapeutic efficacy. Currently, the combination of advanced nanoparticles and novel therapeutic strategies is the most active research area in periodontitis treatment. In this review, we first introduce the pathogenesis of periodontitis, and then summarize the state-of-the-art nanotherapeutic strategies based on the triple concerto of antibacterial activity, immunomodulation and periodontium regeneration, particularly focusing on the therapeutic mechanism and ingenious design of nanomedicines. Finally, the challenges and prospects of nano therapy for periodontitis are discussed from the perspective of current treatment problems and future development trends.

Fibulin-2: A potential regulator of immune dysfunction after bone trauma

OBJECTIVES

To reveal the relationship between the fibulin-2 protein and immune dysfunction after bone trauma.

METHODS

Individuals who were admitted to the study were divided into a bone trauma group, a recovered from bone trauma group and a volunteer without bone trauma group based on the reason for admission. Fibulin-2 levels in the three groups were compared. Fibulin-2-knockout (fibulin-2-/- ) mice and wild-type (WT) mice were used to detect susceptibility to infection. Hematoxylin and eosin (HE) staining and immunohistochemical staining were employed to observe pathological changes in each organ from fibulin-2-/- mice and WT mice.

RESULTS

In total, 132 patients were enrolled in this study. The fibulin-2 level in the bone trauma group was lower than that in the recovered bone trauma group (3.39 ± 1.41 vs. 4.30 ± 1.38 ng/mL, t = 2.948, p < .05) and also lower than that in the volunteers without bone trauma group (3.39 ± 1.41 vs. 4.73 ± 1.67 ng/mL, t = 4.135, p < .05). Fibulin-2-/- mice are more prone to infection. Compared with those in WT mice, spleen function and thymus function in fibulin-2-/- mice were impaired. Immunohistochemical staining revealed that compared with those in WT mice, significantly fewer CD4+ T cells, CD8+ T cells, and CD19+ B cells were noted in the spleen and thymus of fibulin-2-/- mice.

CONCLUSIONS

The plasma fibulin-2 level was lower in patients with bone trauma. Decreased fibulin-2 is associated with immune dysfunction after bone trauma.

Smart stimuli-responsive hydrogels for drug delivery in periodontitis treatment

Periodontitis is a chronic inflammatory disease initiated by pathogenic biofilms and host immunity that damages tooth-supporting tissues, including the gingiva, periodontal ligament and alveolar bone. The physiological functions of the oral cavity, such as saliva secretion and chewing, greatly reduce the residence of therapeutic drugs in the area of a periodontal lesion. In addition, complex and diverse pathogenic mechanisms make effectively treating periodontitis difficult. Therefore, designing advanced local drug delivery systems and rational therapeutic strategies are the basis for successful periodontitis treatment. Hydrogels have attracted considerable interest in the field of periodontitis treatment due to their biocompatibility, biodegradability and convenient administration to the periodontal pocket. In recent years, the focus of hydrogel research has shifted to smart stimuli-responsive hydrogels, which can undergo flexible sol-gel transitions in situ and control drug release in response to stimulation by temperature, light, pH, ROS, glucose, or enzymes. In this review, we systematically introduce the development and rational design of emerging smart stimuli-responsive hydrogels for periodontitis treatment. We also discuss the state-of-the-art therapeutic strategies of smart hydrogels based on the pathogenesis of periodontitis. Additionally, the challenges and future research directions of smart hydrogels for periodontitis treatment are discussed from the perspective of developing efficient hydrogel delivery systems and potential clinical applications.

Immune infiltration and diagnostic value of immune-related genes in periodontitis using bioinformatics analysis

BACKGROUND AND OBJECTIVES

Periodontitis, which is a chronic inflammatory periodontal disease resulting in destroyed periodontal tissue, is the leading cause of tooth loss in adults. Many studies have found that inflammatory immune responses are involved in the risk of periodontal tissue damage. Therefore, we analyzed the association between immunity and periodontitis using bioinformatics methods to further understand this disease.

MATERIALS AND METHODS

First, the expression profiles of periodontitis and healthy samples were downloaded from the GEO database, including a training dataset GSE16134 and an external validation dataset GSE10334. Then, differentially expressed genes were identified using the limma package. Subsequently, immune cell infiltration was calculated by using the CIBERSORT algorithm. We further identified genes linking periodontitis and immunity from the ImmPort and DisGeNet databases. In addition, some of them were selected to construct a diagnostic model via a logistic stepwise regression analysis.

RESULTS AND CONCLUSIONS

Two hundred sixty differentially expressed genes were identified and found to be involved in responses to bacterial and immune-related processes. Subsequently, immune cell infiltration analysis demonstrates significant differences in the abundance of most immune cells between periodontitis and healthy samples, especially in plasma cells. These results suggested that immunity doses play a non-negligible role in periodontitis. Twenty-one genes linking periodontitis and immunity were further identified. And nine hub genes of them were identified that may be key genes involved in the development of periodontitis. Gene ontology analyses showed that these genes are involved in response to molecules of bacterial origin, cell chemotaxis, and response to chemokines. In addition, three genes of them were selected to construct a diagnostic model. And its good diagnostic performance was demonstrated by the receiver operating characteristic curves, with an area under the curve of 0.9424 for the training dataset and 0.9244 for the external validation dataset.