Transcriptome analysis reveals mucin 4 to be highly associated with periodontitis and identifies pleckstrin as a link to systemic diseases

Computational approaches to investigate the relationship between periodontitis and cardiovascular diseases for precision medicine

Periodontitis is a highly prevalent inflammatory illness that leads to the destruction of tooth supporting tissue structures and has been associated with an increased risk of cardiovascular disease (CVD). Precision medicine, an emerging branch of medical treatment, aims can further improve current traditional treatment by personalizing care based on one's environment, genetic makeup, and lifestyle. Genomic databases have paved the way for precision medicine by elucidating the pathophysiology of complex, heritable diseases. Therefore, the investigation of novel periodontitis-linked genes associated with CVD will enhance our understanding of their linkage and related biochemical pathways for targeted therapies. In this article, we highlight possible mechanisms of actions connecting PD and CVD. Furthermore, we delve deeper into certain heritable inflammatory-associated pathways linking the two. The goal is to gather, compare, and assess high-quality scientific literature alongside genomic datasets that seek to establish a link between periodontitis and CVD. The scope is focused on the most up to date and authentic literature published within the last 10 years, indexed and available from PubMed Central, that analyzes periodontitis-associated genes linked to CVD. Based on the comparative analysis criteria, fifty-one genes associated with both periodontitis and CVD were identified and reported. The prevalence of genes associated with both CVD and periodontitis warrants investigation to assess the validity of a potential linkage between the pathophysiology of both diseases.

Single-cell sequencing, spatial transcriptome ad periodontitis: Rethink pathogenesis and classification

OBJECTIVE

This narrative review illuminates on the application of single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) in periodontitis and highlights the probability of relating cell population and gene signatures to the pathogenesis of the disease for a better diagnosis.

METHODS

An electronic search of the literature in the PubMed database for the keywords, "single cell sequencing" OR "spatial transcriptomics" and "periodontitis" OR "gingiva" OR "oral mucosa" yielded 486 research articles and reviews. After filtering duplicates and careful curation, 22 papers conducted in humans were retained.

RESULTS

The molecular mechanisms underlying periodontitis are complex and involve the interaction of multiple cells and various gene expressions. Most residing cells in periodontal tissues participate in maintaining homeostasis and health, while in addition to infiltrating immune cells contribute to the fight against the bacterial insult.

CONCLUSION

scRNA-seq and ST have provided new insights into the cellular and molecular changes associated with periodontitis for a better diagnosis and clinical outcome. New functions of cells and genes are revealed with these techniques; however, no cells or gene signatures are attributed to periodontitis so far.

In Vivo Regulation of Active Matrix Metalloproteinase-8 (aMMP-8) in Periodontitis: From Transcriptomics to Real-Time Online Diagnostics and Treatment Monitoring

BACKGROUND

This study investigated in vivo regulation and levels of active matrix metalloproteinase-8 (aMMP-8), a major collagenolytic protease, in periodontitis.

METHODS

Twenty-seven adults with chronic periodontitis (CP) and 30 periodontally healthy controls (HC) were enrolled in immunohistochemistry and transcriptomics analytics in order to assess Treponema denticola (Td) dentilisin and MMP-8 immunoexpression, mRNA expression of MMP-8 and its regulators (IL-1β, MMP-2, MMP-7, TIMP-1). Furthermore, the periodontal anti-infective treatment effect was monitored by four different MMP-8 assays (aMMP-8-IFMA, aMMP-8-Oralyzer, MMP-8-activity [RFU/minute], and total MMP-8 by ELISA) among 12 CP (compared to 25 HC).

RESULTS

Immunohistochemistry revealed significantly more Td-dentilisin and MMP-8 immunoreactivities in CP vs. HC. Transcriptomics revealed significantly elevated IL-1β and MMP-7 RNA expressions, and MMP-2 RNA was slightly reduced. No significant differences were recorded in the relatively low or barely detectable levels of MMP-8 mRNAs. Periodontal treatment significantly decreased all MMP-8 assay levels accompanied by the assessed clinical indices (periodontal probing depths, bleeding-on-probing, and visual plaque levels). However, active but not total MMP-8 levels persisted higher in CP than in periodontally healthy controls.

CONCLUSION

In periodontal health, there are low aMMP-8 levels. The presence of Td-dentilisin in CP gingivae is associated with elevated aMMP-8 levels, potentially contributing to a higher risk of active periodontal tissue collagenolysis and progression of periodontitis. This can be detected by aMMP-8-specific assays and online/real-time aMMP-8 chair-side testing.

Comprehensive analysis identifies crucial genes associated with immune cells mediating progression of carotid atherosclerotic plaque

BACKGROUNDS

Carotid atherosclerosis is prone to rupture and cause ischemic stroke in advanced stages of development. Our research aims to provide markers for the progression of atherosclerosis and potential targets for its treatment.

METHODS

We performed a thorough analysis using various techniques including DEGs, GO/KEGG, xCell, WGCNA, GSEA, and other methods. The gene expression omnibus datasets GSE28829 and GSE43292 were utilized for this comprehensive analysis. The validation datasets employed in this study consisted of GSE41571 and GSE120521 datasets. Finally, we validated PLEK by immunohistochemistry staining in clinical samples.

RESULTS

Using the WGCNA technique, we discovered 636 differentially expressed genes (DEGs) and obtained 12 co-expression modules. Additionally, we discovered two modules that were specifically associated with atherosclerotic plaque. A total of 330 genes that were both present in DEGs and WGCNA results were used to create a protein-protein network in Cytoscape. We used four different algorithms to get the top 10 genes and finally got 6 overlapped genes (TYROBP, ITGB2, ITGAM, PLEK, LCP2, CD86), which are identified by GSE41571 and GSE120521 datasets. Interestingly, the area under curves (AUC) of PLEK is 0.833. Besides, we found PLEK is strongly positively correlated with most lymphocytes and myeloid cells, especially monocytes and macrophages, and negatively correlated with most stromal cells (e.g, neurons, myocytes, and fibroblasts). The expression of PLEK were consistent with the immunohistochemistry results.

CONCLUSIONS

Six genes (TYROBP, ITGB2, ITGAM, PLEK, LCP2, CD86) were found to be connected with carotid atherosclerotic plaques and PLEK may be an important biomarker and a potential therapeutic target.

Identification of key genes as potential diagnostic and therapeutic targets for comorbidity of myasthenia gravis and COVID-19

Introduction

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder. Coronavirus disease 2019 (COVID-19) has a significant impact on the health and quality of life of MG patients and may even trigger the onset of MG in some cases. With the worldwide development of the COVID-19 vaccination, several new-onset MG cases and exacerbations following the COVID-19 vaccines have been acknowledged. The potential link between myasthenia gravis (MG) and COVID-19 has prompted the need for further investigation into the underlying molecular mechanism.

Methods and results

The differential expression analysis identified six differentially expressed genes (DEGs) shared by myasthenia gravis (MG) and COVID-19, namely SAMD9, PLEK, GZMB, JUNB, NR4A1, and NR1D1. The relationship between the six common genes and immune cells was investigated in the COVID-19 dataset. The predictive value of the shared genes was assessed and a nomogram was constructed using machine learning algorithms. The regulatory miRNAs, transcription factors and small molecular drugs were predicted, and the molecular docking was carried out by AutoDock.

Discussion

We have identified six common DEGs of MG and COVID-19 and explored their immunological effects and regulatory mechanisms. The result may provide new insights for further mechanism research.

Caspase-3 and gasdermin E mediate macrophage pyroptosis in periodontitis

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease linked to pyroptosis, an inflammatory cell death process. Macrophages are essential for maintaining microenvironment homeostasis, which is crucial for periodontal health. This study explores the mechanisms underlying the relationship between macrophage pyroptosis and periodontitis.

METHODS

Expression of the pyroptosis marker gasdermin E (GSDME) and the macrophage surface marker CD68 was examined by immunofluorescence double staining in healthy and periodontitis gingival tissues. In an in vitro pyroptosis model, RAW264.7 cells were irritated using Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) after treatment with either a nuclear factor kappa-B (NF-κB) agonist or inhibitor. The mRNA and protein levels of NF-κB, caspase-3, GSDME, and interleukin-1β (IL-1β) were evaluated through qRT-PCR, western blotting, and ELISA techniques.

RESULTS

GSDME and CD68 were heavily elevated in inflamed gingival tissues compared to healthy tissues and co-localized in the same region. Furthermore, exposure to P. gingivalis-LPS resulted in a significant upregulation of NF-κB, caspase-3, GSDME, and IL-1β at both the mRNA and protein levels in RAW264.7 cells. NF-κB agonist or inhibitor pretreatment enhanced or inhibited these effects.

CONCLUSIONS

GSDME-mediated macrophage pyroptosis is implicated in periodontitis. Based on in vitro experiments, P. gingivalis-LPS causes pyroptosis in RAW264.7 cells through the caspase-3/GSDME pathway. Furthermore, NF-κB regulates this pyroptotic pathway.

Integrated Bioinformatic Analysis of Differentially Expressed Genes Associated with Wound Healing

OBJECTIVE

Wound healing is a complex process involving the coordinated interaction of various genes and molecular
pathways. The study aimed to uncover novel therapeutic targets, biomarkers and candidate genes for drug development
to improve successful wound repair interventions.
Materials and Methods: This study is a network-meta analysis study. Nine wound healing microarray datasets obtained
from the Gene Expression Omnibus (GEO) database were used for this study. Differentially expressed genes (DEGs)
were described using the Limma package and shared genes were used as input for weighted gene co-expression
network analysis. The Gene Ontology analysis was performed using the EnrichR web server, and construction of a
protein-protein interaction (PPI) network was achieved by the STRING and Cytoscape.
Results: A total of 424 DEGs were determined. A co-expression network was constructed using 7692 shared genes
between nine data sets, resulting in the identification of seven modules. Among these modules, those with the top 20
genes of up and down-regulation were selected. The top down-regulated genes, including TJP1, SEC61A1, PLEK,
ATP5B, PDIA6, PIK3R1, SRGN, SDC2, and RBBP7, and the top up-regulated genes including RPS27A, EEF1A1,
HNRNPA1, CTNNB1, POLR2A, CFL1, CSNk1E, HSPD1, FN1, and AURKB, which can potentially serve as therapeutic
targets were identified. The KEGG pathway analysis found that the majority of the genes are enriched in the "Wnt
signaling pathway".
Conclusion: In our study of nine wound healing microarray datasets, we identified DEGs and co-expressed modules
using WGCNA. These genes are involved in important cellular processes such as transcription, translation, and posttranslational
modifications. We found nine down-regulated genes and ten up-regulated genes, which could serve as
potential therapeutic targets for further experimental validation. Targeting pathways related to protein synthesis and cell
adhesion and migration may enhance wound healing, but additional experimental validation is needed to confirm the
effectiveness and safety of targeted interventions.

Altered expression of MZB1 in periodontitis: A possible link to disease pathogenesis

BACKGROUND

Our previous study explored the molecular signatures of generalized aggressive periodontitis (GAgP) using gingival tissues through omics-based-whole-genome transcriptomic analysis. This continuation study aimed to investigate the whole protein profiling of these gingival samples through liquid chromatography-mass spectroscopy/mass spectroscopy (LC-MS/MS) analysis and to validate the identified proteins through immunohistochemistry to provide further evidence for the quality of the results.

METHODS

In previous study, gene expression patterns were identified in gingival tissues from 23 GAgP and 25 control individuals. In the current study, comparative proteomic analysis was performed on isolated proteins from the same study groups using LC-MS/MS analysis. The data from the transcriptomics study published before and the proteomics data were integrated to reveal any common genes and proteins. Additionally, immunohistochemical analysis was conducted to further investigate the findings.

RESULTS

The most upregulated proteins in patients compared to controls were ITGAM, AZU1, MMP9, BPI, UGGG1, MZB1, TRFL, PDIA6, PRDX4, and PLG. The top six pathways associated with these proteins were involved in innate immune system, post-translational protein phosphorylation, interleukin-4 and -13 signaling, toll-like receptors cascades, and extracellular matrix organization. Based on the integration and validation analysis of transcriptomics and proteomics data, as well as immunohistochemical analysis, MZB1 was identified as a shared gene and protein that were upregulated in the patients.

CONCLUSIONS

MZB1 is a protein that is involved in the development of B cells and the production of antibodies. Its upregulation in periodontitis suggests that there may be a dysregulation of the immune response in this condition, and MZB1 may be a potent biomarker for periodontitis.

Higher expression of PLEK and LY86 as the potential biomarker of carotid atherosclerosis

Carotid atherosclerosis (AS) occurs in atherosclerotic lesions of the carotid artery, which can lead to transient ischemic attack and stroke in severe cases. However, the relationship between pleckstrin (PLEK) and lymphocyte antigen 86 (LY86) and carotid AS remains unclear. The carotid AS datasets GSE43292 and GSE125771 were downloaded from the gene expression omnibus database. Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis was performed. Construction and analysis of protein-protein interaction network. Functional enrichment analysis, gene set enrichment analysis and comparative toxicogenomics database analysis were performed. TargetScan screened miRNAs that regulated central DEGs. A total of 305 DEGs were identified. According to gene ontology analysis, they were mainly enriched in immune system processes, extracellular regions and cytokine binding. Kyoto encyclopedia of genes and genomes analysis showed that the target cells were mainly enriched in Rap1 signal pathway, B cell receptor signal pathway and PPAR signal pathway. In the enrichment project of metascape, the reaction to bacteria, cell activation and chemotaxis can be seen in the enrichment project of gene ontology. Total 10 core genes (TYROBP, FCER1G, PLEK, LY86, IL10RA, ITGB2, LCP2, FCGR2B, CD86, CCR1) were obtained by protein-protein interaction network construction and analysis. Core genes (PLEK, LY86, IL10RA, ITGB2, and LCP2) were highly expressed in carotid AS samples and lowly expressed in normal samples. Comparative toxicogenomics database analysis showed that 5 genes were associated with pneumonia, inflammation, necrosis, and drug allergy. PLEK and LY86 genes are highly expressed in carotid AS. The higher the expression of PLEK and LY86, the worse the prognosis is.

Identification and Validation of Immune-Related Genes Diagnostic for Progression of Atherosclerosis and Diabetes

Background

Atherosclerosis and type 2 diabetes mellitus contribute to a large part of cardiovascular events, but the underlying mechanism remains unclear. In this study, we focused on identifying the linking genes of the diagnostic biomarkers and effective therapeutic targets associated with these two diseases.

Methods

The transcriptomic datasets of atherosclerosis and type 2 diabetes mellitus were obtained from the GEO database. Differentially expressed genes analysis was performed by R studio software, and differential analysis including functional enrichment, therapeutic small molecular agents prediction, and protein-protein interaction analysis were applied to the common shared differentially expressed genes. Hub genes were identified and further validated using an independent dataset and clinical samples. Furthermore, we measured the expression correlations, immune cell infiltration, and diagnostic capability of the three key genes.

Results

We screened out 28 up-regulated and six down-regulated common shared differentially expressed genes. Functional enrichment analysis showed that cytokines and immune activation were involved in the development of these two diseases. Six small molecules with the highest absolute enrichment value were identified. Three critical genes (CD4, PLEK, and THY1) were further validated both in validation sets and clinical samples. The gene correlation analysis showed that CD4 was strongly positively correlated with PLEK, and ROC curves confirmed the good discriminatory capacity of CD4 and PLEK in two diseases.

We have established the co-expression network between atherosclerosis lesions progressions and type 2 diabetes mellitus, and identified CD4 and PLEK as key genes in the two diseases, which may facilitate both development of diagnosis and therapeutic strategies.

Bioinformatics methods in biomarkers of preeclampsia and associated potential drug applications

Background

Preeclampsia is a pregnancy-related condition that causes high blood pressure and proteinuria after 20 weeks of pregnancy. It is linked to increased maternal mortality, organ malfunction, and foetal development limitation. In this view, there is a need critical to identify biomarkers for the early detection of preeclampsia. The objective of this study is to discover critical genes and explore medications for preeclampsia treatment that may influence these genes.

Methods

Four datasets, including GSE10588, GSE25906, GSE48424 and GSE60438 were retrieved from the Gene Expression Omnibus database. The GSE10588, GSE25906, and GSE48424 datasets were then removed the batch effect using the “sva” R package and merged into a complete dataset. The differentially expressed genes (DEGs) were identified using the “limma” R package. The potential small-molecule agents for the treatment of PE was further screened using the Connective Map (CMAP) drug database based on the DEGs. Further, Weight gene Co-expression network (WGNCA) analysis was performed to identified gene module associated with preeclampsia, hub genes were then identified using the logistic regression analysis. Finally, the immune cell infiltration level of genes was evaluated through the single sample gene set enrichment analysis (ssGSEA).

Results

A total of 681 DEGs (376 down-regulated and 305 up-regulated genes) were identified between normal and preeclampsia samples. Then, Dexamethasone, Prednisone, Rimexolone, Piretanide, Trazodone, Buflomedil, Scoulerin, Irinotecan, and Camptothecin drugs were screened based on these DEGs through the CMAP database. Two modules including yellow and brown modules were the most associated with disease through the WGCNA analysis. KEGG analysis revealed that the chemokine signaling pathway, Th1 and Th2 cell differentiation, B cell receptor signalling pathway and oxytocin signalling pathway were significantly enriched in these modules. Moreover, two key genes, PLEK and LEP were evaluated using the univariate and multivariate logistic regression analysis from the hub modules. These two genes were further validated in the external validation cohort GSE60438 and qRT-PCR experiment. Finally, we evaluated the relationship between immune cell and two genes.

Conclusion

In conclusion, the present study investigated key genes associated with PE pathogenesis that may contribute to identifying potential biomarkers, therapeutic agents and developing personalized treatment for PE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08937-3.

Expression of periodontitis susceptibility genes in human gingiva using single-cell RNA sequencing

OBJECTIVE

Single-cell transcriptomics was used to determine the possible cell-type specificity of periodontitis susceptibility genes.

BACKGROUND

The last decade has witnessed remarkable advances in the field of human genomics. Despite many advances, the genetic factors associated with or contributing to the periodontitis pathogenesis have only been identified to a limited extent and are often poorly validated. Confirming whether a given single nucleotide polymorphism has an association with periodontitis requires a robust mechanistic explanation on the functional consequences of a given genetic variant.

METHODS

We globally assessed the expression of 26 disease-associated genes identified by GWAS within the gingival mucosa. A total of 12 411 cells from 4 different donors were analysed. Differentially expressed genes were analysed using Seurat, a non-parametric Wilcoxon rank sum test. The minimum threshold for significance was defined as p < .05.

RESULTS

This exploration at a cellular-level suggests diverse populations contributing to disease pathogenesis, with macrophages expressing a higher number of the analysed disease-associated genes. IL1B, PTGS2, FCGR2A, IL10 and IL1A specifically showed a more restricted expression in the myeloid lineages.

CONCLUSION

This short report combines human genetics and single-cell genomics to better understand periodontitis by mapping variants to predict their cells of action and putative functions. These findings seem to suggest that innate cell dysfunction is linked to disease susceptibility.

Classifying Integrated Signature Molecules in Macrophages of Rheumatoid Arthritis, Osteoarthritis, and Periodontal Disease: An Omics-Based Study

Rheumatoid arthritis (RA), osteoarthritis (OA), and periodontal disease (PD) are chronic inflammatory diseases that are globally prevalent, and pose a public health concern. The search for a potential mechanism linking PD to RA and OA continues, as it could play a significant role in disease prevention and treatment. Recent studies have linked RA, OA, and PD to Porphyromonas gingivalis (PG), a periodontal bacterium, through a similar dysregulation in an inflammatory mechanism. This study aimed to identify potential gene signatures that could assist in early diagnosis as well as gain insight into the molecular mechanisms of these diseases. The expression data sets with the series IDs GSE97779, GSE123492, and GSE24897 for macrophages of RA, OA synovium, and PG stimulated macrophages (PG-SM), respectively, were retrieved and screened for differentially expressed genes (DEGs). The 72 common DEGs among RA, OA, and PG-SM were further subjected to gene–gene correlation analysis. A GeneMANIA interaction network of the 47 highly correlated DEGs comprises 53 nodes and 271 edges. Network centrality analysis identified 15 hub genes, 6 of which are DEGs (API5, ATE1, CCNG1, EHD1, RIN2, and STK39). Additionally, two significantly up-regulated non-hub genes (IER3 and RGS16) showed interactions with hub genes. Functional enrichment analysis of the genes showed that “apoptotic regulation” and “inflammasomes” were among the major pathways. These eight genes can serve as important signatures/targets, and provide new insights into the molecular mechanism of PG-induced RA, OA, and PD.

Pleckstrin Levels Are Increased in Patients with Chronic Periodontitis and Regulated via the MAP Kinase-p38α Signaling Pathway in Gingival Fibroblasts

Chronic periodontitis (CP) is a bacteria-driven inflammatory disease characterized by the breakdown of gingival tissue, the periodontal ligament, and alveolar bone, leading ultimately to tooth loss. We previously reported the pleckstrin gene (PLEK) to be highly upregulated in gingival tissue of patients with CP and the only gene concurrently upregulated in other inflammatory diseases including rheumatoid arthritis and cardiovascular diseases. Using saliva from 169 individuals diagnosed with CP and healthy controls, we investigated whether pleckstrin could serve as a novel biomarker of periodontitis. Additionally, we explored signal pathways involved in the regulation of PLEK using human gingival fibroblasts (HGFs). Pleckstrin levels were significantly higher (p < 0.001) in the saliva samples of patients with CP compared to controls and closely associated with CP severity. Immunohistochemical analysis revealed the expression of pleckstrin in inflammatory cells and gingival fibroblasts of CP patients. To explore the signal pathways involved in pleckstrin regulation, we stimulated HGFs with either interleukin-1β (IL-1β) or lipopolysaccharides (LPS) alone, or in combination with inhibitors targeting c-Jun N-terminal kinase, tyrosine kinase, protein kinase C, or p38 MAP kinase. Results showed that IL-1β and LPS significantly increased PLEK mRNA and pleckstrin protein levels. VX-745, the p38 MAP kinase inhibitor significantly decreased IL-1β- and LPS-induced pleckstrin levels at both the mRNA and the protein level. Together, these findings show that pleckstrin could serve as a salivary biomarker for the chronic inflammatory disease periodontitis and a regulator of inflammation via the p38 MAP kinase pathway.

Expression and significance of mucin-4 and matrix metalloproteinase-7 in peri-implant disease

OBJECTIVES

This study aims to detect the levels of mucin (MUC)-4, metalloproteinase (MMP)-7, and MMP-8 in peri-implant crevicular fluid (PICF) and investigate whether the novel combinations of MMP-7 and MUC-4 are effective markers of peri-implant diseases, particularly when used in the PICF of healthy individuals, to provide a theoretical basis for finding a novel reference index that can aid the diagnosis, evaluation, and treatment of peri-implant diseases.

METHODS

A total of 63 subjects with 2-5 years of upper prosthesis loading were selected according to inclusion and exclusion criteria, composed of 24 controls and 39 patients with peri-implantitis (PI) group. MUC-4, MMP-7, and MMP-8 levels were detected through enzyme linked immunosorbent assay (ELISA).

RESULTS

No significant differences in age, sex, and other parameters were found between the PI and control groups. The PI group had higher MMP-7 and MMP-8 expression levels (P<0.05) but lower MUC-4 level (P<0.001). Correlation analysis showed that MMP-7 was positively correlated with pocket probing depth (PPD) (r=0.451, P<0.001); MMP-8 was positively correlated with PPD, bleeding on probing (BOP), and gingival index (GI) (r=0.619, P<0.001; r=0.478, P<0.001; r=0.332, P=0.009). MUC-4 was negatively correlated with PPD, BOP, and GI (r=-0.492, P<0.001; r=-0.321, P=0.010; r=-0.396, P=0.001). MMP-7, MMP-8, and MUC-4 had certain diagnostic efficacy for PI. MMP-8 exhibited the best diagnostic efficacy for PI. When the cutoff value of MMP-8 was >21.21, the area under the curve (AUC) was 0.868, and the sensitivity and specificity for the diagnosis of PI were 0.96 and 0.68, respectively. The diagnostic efficacy of MMP-7 and MUC-4 parallel diagnostic models was higher than that of each factor, and the diagnostic sensitivity of the model for PI was 0.96, and the specificity was 0.56.

CONCLUSIONS

Differences in MMP-7 and MUC-4 levels were found between the inflammation and control groups and may be diagnostic indicators for predicting PI; combinations of MMP-7 and MUC-4 had a good diagnostic value for inflammation.

PANoptosis: A New Insight Into Oral Infectious Diseases

The oral microbiome, one of the most complex and intensive microbial ecosystems in the human body, comprises bacteria, archaea, fungi, protozoa, and viruses. Dysbiosis of the oral microbiome is the initiating factor that leads to oral infectious diseases. Infection is a sophisticated biological process involving interplay between the pathogen and the host, which often leads to activation of programmed cell death. Studies suggest that pyroptosis, apoptosis, and necroptosis are involved in multiple oral infectious diseases. Further understanding of crosstalk between cell death pathways has led to pyroptosis, apoptosis, and necroptosis being integrated into a single term: PANoptosis. PANoptosis is a multifaceted agent of the immune response that has important pathophysiological relevance to infectious diseases, autoimmunity, and cancer. As such, it plays an important role in innate immune cells that detect and eliminate intracellular pathogens. In addition to the classical model of influenza virus-infected and Yersinia-infected macrophages, other studies have expanded the scope of PANoptosis to include other microorganisms, as well as potential roles in cell types other than macrophages. In this review, we will summarize the pathophysiological mechanisms underlying inflammation and tissue destruction caused by oral pathogens. We present an overview of different pathogens that may induce activation of PANoptosis, along with the functional consequences of PANoptosis in the context of oral infectious diseases. To advance our understanding of immunology, we also explore the strategies used by microbes that enable immune evasion and replication within host cells. Improved understanding of the interplay between the host and pathogen through PANoptosis will direct development of therapeutic strategies that target oral infectious diseases.

Emerging Roles of Pleckstrin-2 Beyond Cell Spreading

Pleckstrin-2 is a member of pleckstrin family with well-defined structural features that was first identified in 1999. Over the past 20 years, our understanding of PLEK2 biology has been limited to cell spreading. Recently, increasing evidences support that PLEK2 plays important roles in other cellular events beyond cell spreading, such as erythropoiesis, tumorigenesis and metastasis. It serves as a potential diagnostic and prognostic biomarker as well as an attractive target for the treatment of cancers. Herein, we summary the protein structure and molecular interactions of pleckstrin-2, with an emphasis on its regulatory roles in tumorigenesis.

Transcript levels of cytokine coding genes in peripheral blood and tissues of patients with periodontitis

Periodontal diseases are common conditions in almost all age groups and a public health problem. Numerous risk factors have been demonstrated for this condition. The main mechanism of tissue destruction in the periodontitis is the functional interactions between microbial pathogens and host immune responses, thus cytokines have crucial roles in the pathogenesis periodontitis. Our previous study has demonstrated the susceptibility role of HLA-DRB1*04 allele in development of this disease. So, the individuals who were positive for HLA-DRB1*04 allele were excluded. We aimed to appraise the function of cytokines in the pathogenesis of periodontitis via assessment of tissue and blood levels of a number of cytokine coding genes, namely IL-1B, CXCL8, IL-17, IFNG, TGFB and TNFA1. Expressions of IFNG, IL-17, TGFB and TNFA1 were significantly higher in the peripheral blood of individuals with periodontitis compared with unaffected persons (Posterior beta = 1.91, P value = 0.043; Posterior beta = 1.84, P value = 0.033; Posterior beta = 0.713, P value = 0.009 and Posterior beta = 2.85, P value = 0.001, respectively). Moreover, expression of IL-17 was higher in females compared with males (Posterior beta = 1.47, P value = 0.036). As the interaction effect between gender and group was remarkable for IL-17 expression, we further conducted subgroup analysis within gender group. Expression of IL-17 was higher in male patients compared with unaffected males (Posterior beta = 1.9, P value = 0.048). We did not detect any significant difference in the expression of these cytokines in tissues obtained from affected individuals and unaffected controls. Therefore, our results imply dysregulation of cytokine coding genes in patients with periodontitis and warrant further mechanistical studies.

Co-pathogens in Periodontitis and Inflammatory Bowel Disease

Localized inflammatory lesions in one area of the body may affect other distant organs through various modes of transmission thus initiating secondary inflammatory infections. Periodontal disease (PD) and inflammatory bowel disease (IBD) have been shown to coexist. Periodontitis is a multifactorial inflammatory disease, and dental plaque is considered to be the initial risk factor. Individuals with genetic susceptibility are more likely to develop periodontitis when exposed to external stimuli. IBD is affected by host genetics, immunoregulation, daily diet, and the gut microbiota, and its risk factors appear to be shared with those of PD. However, the key etiologies of both diseases remain unclear, thus hindering the exploration of possible links between IBD and PD. Recent studies and systematic reviews have focused on evidence-based statistics of the prevalence and clinical manifestations of both diseases, but discussions of the microbial etiological correlation between periodontitis and intestinal inflammation are scarce. Here, we summarize the potential common pathogenic microorganisms that may serve as bridges between the two diseases. Studies have shown that invasive microorganisms such as Porphyromonas gingivalis, Fusobacterium nucleatum, Klebsiella spp. and Campylobacter spp. play key roles in the comorbidity of PD and IBD.

Single-Cell RNA Sequencing Identifies New Inflammation-Promoting Cell Subsets in Asian Patients With Chronic Periodontitis

Periodontitis is a highly prevalent chronic inflammatory disease leading to periodontal tissue breakdown and subsequent tooth loss, in which excessive host immune response accounts for most of the tissue damage and disease progression. Despite of the imperative need to develop host modulation therapy, the inflammatory responses and cell population dynamics which are finely tuned by the pathological microenvironment in periodontitis remained unclear. To investigate the local microenvironment of the inflammatory response in periodontitis, 10 periodontitis patients and 10 healthy volunteers were involved in this study. Single-cell transcriptomic profilings of gingival tissues from two patients and two healthy donors were performed. Histology, immunohistochemistry, and flow cytometry analysis were performed to further validate the identified cell subtypes and their involvement in periodontitis. Based on our single-cell resolution analysis, we identified HLA-DR-expressing endothelial cells and CXCL13+ fibroblasts which are highly associated with immune regulation. We also revealed the involvement of the proinflammatory NLRP3+ macrophages in periodontitis. We further showed the increased cell-cell communication between macrophage and T/B cells in the inflammatory periodontal tissues. Our data generated an intriguing catalog of cell types and interaction networks in the human gingiva and identified new inflammation-promoting cell subtypes involved in chronic periodontitis, which will be helpful in advancing host modulation therapy.

A rare genomic duplication in 2p14 underlies autosomal dominant hearing loss DFNA58

Here we define a ~200 Kb genomic duplication in 2p14 as the genetic signature that segregates with postlingual progressive sensorineural autosomal dominant hearing loss (HL) in 20 affected individuals from the DFNA58 family, first reported in 2009. The duplication includes two entire genes, PLEK and CNRIP1, and the first exon of PPP3R1 (protein coding), in addition to four uncharacterized long non-coding (lnc) RNA genes and part of a novel protein-coding gene. Quantitative analysis of mRNA expression in blood samples revealed selective overexpression of CNRIP1 and of two lncRNA genes (LOC107985892 and LOC102724389) in all affected members tested, but not in unaffected ones. Qualitative analysis of mRNA expression identified also fusion transcripts involving parts of PPP3R1, CNRIP1 and an intergenic region between PLEK and CNRIP1, in the blood of all carriers of the duplication, but were heterogeneous in nature. By in situ hybridization and immunofluorescence, we showed that Cnrip1, Plek and Ppp3r1 genes are all expressed in the adult mouse cochlea including the spiral ganglion neurons, suggesting changes in expression levels of these genes in the hearing organ could underlie the DFNA58 form of deafness. Our study highlights the value of studying rare genomic events leading to HL, such as copy number variations. Further studies will be required to determine which of these genes, either coding proteins or non-coding RNAs, is or are responsible for DFNA58 HL.

Genetic susceptibility to acute graft versus host disease in pediatric patients undergoing HSCT

The most frequent complication of allogeneic hematopoietic stem cell transplantation is acute Graft versus Host Disease (aGVHD). Proliferation and differentiation of donor T cells initiate inflammatory response affecting the skin, liver, and gastrointestinal tract. Besides recipient-donor HLA disparities, disease type, and the conditioning regimen, variability in the non-HLA genotype have an impact on aGVHD onset, and genetic variability of key cytokines and chemokines was associated with increased risk of aGVHD. To get further insight into the recipient genetic component of aGVHD grades 2-4 in pediatric patients, we performed an exome-wide association study in a discovery cohort (n = 87). Nine loci sustained correction for multiple testing and were analyzed in a validation group (n = 168). Significant associations were replicated for ERC1 rs1046473, PLEK rs3816281, NOP9 rs2332320 and SPRED1 rs11634702 variants through the interaction with non-genetic factors. The ERC1 variant was significant among patients that received the transplant from HLA-matched related individuals (p = 0.03), bone marrow stem cells recipients (p = 0.007), and serotherapy-negative patients (p = 0.004). NOP9, PLEK, and SPRED1 effects were modulated by stem cell source, and serotherapy (p < 0.05). Furthermore, ERC1 and PLEK SNPs correlated with aGVHD 3-4 independently of non-genetic covariates (p = 0.02 and p = 0.003). This study provides additional insight into the genetic component of moderate to severe aGVHD.

Skewed inflammation is associated with aberrant interleukin-37 signaling pathway in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a severe global burden on physical, physiological, and mental health. The role of IL-37, a fundamental inhibitor of immunity, in AD was herein explored.

METHOD

Serum levels of IL-37 and T helper (Th) 2-related inflammatory mediators were quantified in subjects with or without AD. The expression of IL-37 receptors was determined by flow cytometry. Proteomics was employed to explore the serum protein profile and novel biomarkers. In vitro cell model, 3D-keratinocytes mimicking skin model, and the serum of subjects with or without AD were investigated to verify the proteomic results.

RESULTS

AD patients were found to present with higher levels of total and specific IgE as well as Th2 inflammatory mediators compared with healthy controls (HC). IL-37 level and its receptor IL18Rɑ expression in AD patients were significantly decreased, together with increased population of eosinophils, indicating that the signaling of IL37/IL18Rɑ was dampened. In addition, proteomic analysis revealed a significantly differential protein profile of AD patients compared with HC. IL-37 showed the strongest negative correlation with involucrin, a keratinizing epithelia protein. IL-37 was verified to suppress induced involucrin expression in in vitro skin cell models. AD patients show a significantly higher serum concentration of involucrin compared with HC. Together, our results demonstrated that IL-37 plays a regulatory role in AD. Its deficiency may lead to the aberrant involucrin expression in AD.

CONCLUSIONS

The dysregulation of serum protein and skin disruption in AD is related to the insufficiency of IL-37 and its attenuated anti-inflammatory signaling.

Defining human mesenchymal and epithelial heterogeneity in response to oral inflammatory disease

Human oral soft tissues provide the first barrier of defence against chronic inflammatory disease and hold a remarkable scarless wounding phenotype. Tissue homeostasis requires coordinated actions of epithelial, mesenchymal, and immune cells. However, the extent of heterogeneity within the human oral mucosa and how tissue cell types are affected during the course of disease progression is unknown. Using single-cell transcriptome profiling we reveal a striking remodelling of the epithelial and mesenchymal niches with a decrease in functional populations that are linked to the aetiology of the disease. Analysis of ligand–receptor interaction pairs identify potential intercellular hubs driving the inflammatory component of the disease. Our work establishes a reference map of the human oral mucosa in health and disease, and a framework for the development of new therapeutic strategies.

Host-microbe interactions: Profiles in the transcriptome, the proteome, and the metabolome

Periodontal studies using transcriptomics, proteomics, and metabolomics encompass the collection of mRNA transcripts, proteins, and small-molecule chemicals in the context of periodontal health and disease. The number of studies using these approaches has significantly increased in the last decade and they have provided new insight into the pathogenesis and host-microbe interactions that define periodontal diseases. This review provides an overview of current molecular findings using -omic approaches that underlie periodontal disease, including modulation of the host immune response, tissue homeostasis, and complex metabolic processes of the host and the oral microbiome. Integration of these -omic approaches will broaden our perspective of the molecular mechanisms involved in periodontal disease, advancing and improving the diagnosis and treatment of various stages and forms of periodontal disease.

Long non-coding RNA and mRNA expression profiles in peri-implantitis vs periodontitis

BACKGROUND AND OBJECTIVE

Peri-implantitis is a biofilm-mediated infectious disease that results in progressive loss of implant-supporting bone. As compared to its analogue periodontitis, peri-implantitis is generally known to be more aggressive, with comparatively rapid progression and less predictable treatment outcomes, especially when advanced. An understanding of molecular mechanisms underpinning the similarities and differences between peri-implantitis and periodontitis is essential to develop novel management strategies. This study aimed to compare long non-coding RNAs (lncRNAs) and messenger RNA (mRNA) expression profiles between peri-implantitis and periodontitis.

METHODS

Inflamed soft tissue from peri-implantitis and periodontitis lesions, and healthy gingival tissue controls were analyzed by microarray. Cluster graphs, gene ontology (GO) analysis, and pathway analysis were performed. Quantitative real-time PCR was employed to verify microarray results. The expression levels of RANKL and OPG in the three tissue types were also evaluated, using qRT-PCR. Coding non-coding (CNC) network analyses were performed.

RESULTS

Microarray analyses revealed 1079 lncRNAs and 1003 mRNAs as differentially expressed in peri-implantitis when compared to periodontitis. The cyclooxygenase-2 pathway was the most up-regulated biological process in peri-implantitis as compared to periodontitis, whereas hemidesmosome assembly was the most down-regulated pathway. Osteoclast differentiation was relatively up-regulated, and RANKL/OPG ratio was higher in peri-implantitis than in periodontitis.

CONCLUSIONS

The study demonstrated that peri-implantitis and periodontitis exhibit significantly different lncRNA and mRNA expression profiles, suggesting that osteoclast differentiation-related pathways are comparatively more active in peri-implantitis. These data highlight potential molecular targets for periodontitis and peri-implantitis therapy development.

Porphyromonas gingivalis degrades integrin β1 and induces AIF-mediated apoptosis of epithelial cells

Background: Porphyromonas gingivalis, a major pathogen of chronic periodontitis, adheres to and invades epithelial cells via an interaction between fimbriae and integrin. P. gingivalis proliferation and infection may affect the survival of cells. In this study, we further examined alternative signaling pathways mediating epithelial-cell death induced by P. gingivalis and the role of the cell-adhesion molecule integrin. Methods: Human epithelial KB cells interacted with P. gingivalis to evaluate cell death by Annexin V-propidium iodide (PI) staining. JC-1 staining was used to measure mitochondrial membrane potential (MMP). The mRNA and protein of integrin β1, apoptosis-inducing factor (AIF) and caspase-3 were detected by real-time PCR and western blot. Caspase-3 activity was analyzed by spectrophotometry. Results: P. gingivalis infection downregulated integrin β1 and led to cell detachment in a dose and time-dependent manner. Large amount of P. gingivalis induced MMP depolarization and apoptosis in KB cells. Moreover, P. gingivalis up-regulated AIF, but not activate caspase-3 during apoptosis. In addition, AIF inhibitor N-Phenylmaleimide almost inhibited the P. gingivalis-induced apoptosis. Conclusions: P. gingivalis disrupts epithelial-cell adhesion by degrading integrin β1 and induces caspase-independent, AIF-mediated mitochondrial apoptosis, which may promote the damage of oral tissue.

Identification of Salivary Microbiota and Its Association With Host Inflammatory Mediators in Periodontitis

Periodontitis is a microbial-induced chronic inflammatory disease, which may not only result in tooth loss, but can also contribute to the development of various systemic diseases. The transition from healthy to diseased periodontium depends on microbial dysbiosis and impaired host immune response. Although periodontitis is a common disease as well as associated with various systemic inflammatory conditions, the taxonomic profiling of the salivary microbiota in periodontitis and its association with host immune and inflammatory mediators has not been reported. Therefore, the aim of this study was to identify key pathogens and their potential interaction with the host's inflammatory mediators in saliva samples for periodontitis risk assessment. The microbial 16S rRNA gene sequencing and the levels of inflammatory mediators were performed in saliva samples from patients with chronic periodontitis and periodontally healthy control subjects. The salivary microbial community composition differed significantly between patients with chronic periodontitis and healthy controls. Our analyses identified a number of microbes, including bacteria assigned to Eubacterium saphenum, Tannerella forsythia, Filifactor alocis, Streptococcus mitis/parasanguinis, Parvimonas micra, Prevotella sp., Phocaeicola sp., and Fretibacterium sp. as more abundant in periodontitis, compared to healthy controls. In samples from healthy individuals, we identified Campylobacter concisus, and Veillonella sp. as more abundant. Integrative analysis of the microbiota and inflammatory mediators/cytokines revealed associations that included positive correlations between the pathogens Treponema sp. and Selenomas sp. and the cytokines chitinase 3-like 1, sIL-6Rα, sTNF-R1, and gp130/sIL-6Rβ. In addition, a negative correlation was identified between IL-10 and Filifactor alocis. Our results reveal distinct and disease-specific patterns of salivary microbial composition between patients with periodontitis and healthy controls, as well as significant correlations between microbiota and host-mediated inflammatory cytokines. The positive correlations between the pathogens Treponema sp. and Selenomas sp. and the cytokines chitinase 3-like 1, sIL-6Rα, sTNF-R1, and gp130/sIL-6Rβ might have the future potential to serve as a combined bacteria-host salivary biomarker panel for diagnosis of the chronic infectious disease periodontitis. However, further studies are required to determine the capacity of these microbes and inflammatory mediators as a salivary biomarker panel for periodontitis.

Oral epithelial membrane-associated mucins and transcriptional changes with Sjögren's syndrome

OBJECTIVES

To determine expression and localization of membrane-associated mucins within human keratinized and non-keratinized oral epithelia, and to explore transcriptional changes associated with primary Sjögren's syndrome.

SUBJECTS AND METHODS

Mucin transcripts and glycoproteins were determined by RT-PCR and immunohistochemistry, respectively, in oral keratinized (hard palate) and non-keratinized (buccal) epithelia obtained from three cadavers. Mucin transcripts assessed by quantitative PCR were compared between cells harvested by brushing buccal and palatal epithelia of 25 female primary Sjögren's syndrome patients vs 25 healthy age-matched female control subjects.

RESULTS

In hard palate, MUC4 is absent and MUC1 localized to deeper cell layers. Both mucins are within the apical layers of buccal epithelium. MUC15 is localized throughout all palatal cell layers and in all but the basal layer of buccal epithelia. MUC16, MUC20, and MUC21 glycoproteins are localized within all but the basal cell layer of both tissue types. In buccal cells of primary Sjögren's patients, MUC21 transcripts are down-regulated 3.4-fold and MUC20 2.6-fold. Dysregulation of select epithelial mucins may therefore contribute to xerostomia.

CONCLUSIONS

Differential expression of multiple mucins and down-regulation in Sjögren's syndrome support further study of oral epithelial mucin physiology and pathophysiology, including their functions in hydration and lubrication of the oral mucosal pellicle.

CD8+ Foxp3+ T Cells Affect Alveolar Bone Homeostasis via Modulating Tregs/Th17 During Induced Periodontitis: an Adoptive Transfer Experiment

Periodontitis is a dysbiotic bacteria-mediated disease characterized by periodontal inflammations and alveolar bone damage. Its mechanisms were complicated, involving an inflammation-mediated bone destruction. We sought to determine roles and rules that CD8⁺ regulatory T cells (CD8⁺ Tregs) affect alveolar bone homeostasis during periodontitis. Presence of CD8⁺ Tregs in the gingiva, cervical lymph nodes (CLNs), and spleens of healthy or periodontitis animals was analyzed. CD8⁺ regulatory T cells from periodontitis animals were sorted by magnetic-activated cell sorting and fluorescent-activated cell sorting technique, subsequently injected into recipient animals to set adoptive transfer model. We induced experimental periodontitis on transfer models and equal number healthy animals. Four weeks later, their alveolar bone loss and osteoclast coverage length were measured. We also detected CD8⁺ Tregs, CD4⁺ T cell, CD4⁺ Tregs, Th17 cell, and IL-1β, IL-6, IL-10, IL-17A, RANKL, TGF-β expression in the gingiva, CLNs, and spleen to illustrate possible working mechanism of CD8⁺ regulatory T cells. Periodontitis does not induce significant change on proportion or amount of CD8⁺ Tregs. Adoptive transfer of CD8⁺ Tregs reduces alveolar bone destruction and osteoclast formation. In addition, experimental periodontitis increases percentage of Th17 cells and decreases CD4⁺ Tregs in the gingiva and CLNs. More IL-1β, IL-6, IL-17A, and RANKL, and less IL-10 and TGF-β are also detected in the gingiva and CLNs from animals with periodontitis than the one from healthy animals. Adoptive transfer of CD8⁺ regulatory T cells remedies all above pathological change effectively. We did not find any significant difference in spleen, regardless group and detected items. Outcomes of present study clarify function that CD8⁺ regulatory T cells affect alveolar bone homeostasis, and disclose its possible working mechanisms. CD8⁺ regulatory T cells protect alveolar bone via reducing osteoclastogenesis and modulating local immune response.

Meta-analysis of the association between serum and gingival crevicular fluid matrix metalloproteinase-9 and periodontitis

BACKGROUND

The authors of this meta-analysis evaluated whether there is a difference in the levels of serum and gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-9 between patients with periodontitis and periodontally healthy control participants.

TYPES OF STUDIES REVIEWED

The authors searched PubMed, Embase, the Cochrane Library, and the China Biology Medicine disk databases for eligible studies in which the investigators reported the relationships between MMP-9 levels in serum and GCF and periodontitis. The authors pooled the standardized mean differences (SMDs) and 95% confidence intervals (CIs) from each study to evaluate the difference in the serum and GCF MMP-9 levels between patients with periodontitis and periodontally healthy control participants.

RESULTS

Results of a meta-analysis of 6 case-control studies including a total of 923 healthy control participants and 557 patients with periodontitis indicated that serum MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.60; 95% CI, 0.17 to 3.03; P < .05). Results of a separate meta-analysis of 6 case-control studies including a total of 153 healthy control participants and 189 patients with periodontitis indicated that GCF MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.96; 95% CI, 0.76 to 3.16; P < .01).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The results of the meta-analysis revealed statistically significant differences in the MMP-9 levels in serum and GCF between patients with periodontitis and periodontally healthy control participants. These results cannot be used to confirm causality because the included studies were all case-control studies in which the investigators reported associations. Moreover, readers should view the results with caution because of the considerable heterogeneity among the studies included in the meta-analysis.

T-Probe: An Integrated Microscale Device for Online In Situ Single Cell Analysis and Metabolic Profiling Using Mass Spectrometry

The exploration of single cells reveals cell heterogeneity and biological principle of cellular metabolism. Although a number of mass spectrometry (MS) based single cell MS (SCMS) techniques have been dedicatedly developed with high efficiency and sensitivity, limitations still exist. In this work, we introduced a microscale multifunctional device, the T-probe, which integrates cellular contents extraction and immediate ionization, to implement online in situ SCMS analysis at ambient conditions with minimal sample preparation. With high sensitivity and reproducibility, the T-probe was employed for MS analysis of single HeLa cells under control and anticancer drug treatment conditions. Intracellular species and xenobiotic metabolites were detected, and changes of cellular metabolic profiles induced by drug treatment were measured. Combining SCMS experiments with statistical data analyses, including Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) and two-sample t-test, we provided biological insights into cellular metabolic response to drug treatment. Online MS/MS analysis was conducted at single cell level to identify species of interest, including endogenous metabolites and the drug compound. Using the T-probe SCMS technique combined with comprehensive data analyses, we provide an approach to understanding cellular metabolism and evaluate chemotherapies at the single cell level.

Increased citrullination and expression of peptidylarginine deiminases independently of P. gingivalis and A. actinomycetemcomitans in gingival tissue of patients with periodontitis

BACKGROUND

A relationship between rheumatoid arthritis (RA) and periodontitis has been suggested from findings that individuals with RA are prone to have advanced periodontitis and vice versa. In search of possible common pathogenetic features of these two diseases, we investigated the presence of citrullinated proteins and expression of endogenous peptidylarginine deiminases (PAD2 and PAD4), in periodontal tissue of individuals with periodontitis and healthy controls, in relation to the periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), producing leukotoxin as virulence factor. These two oral bacteria have been suggested to be linked to anti-citrullinated protein antibodies in patients with RA.

METHODS

Gingival tissue biopsies were obtained from 15 patients with periodontitis and 15 individuals without periodontal disease. Presence of CD3-positive lymphocytes, citrullinated proteins, PAD2, PAD4, P. gingivalis as well as A. actinomycetemcomitans and Mannheimia haemolytica produced leukotoxins were analysed by immunohistochemistry, followed by triple-blind semi-quantitative analysis. Mann-Whitney and Fisher's exact tests were used to analyse differences between groups. PADI2 and PADI4 mRNA levels were assessed by RT-qPCR and analysed using Wilcoxon signed rank test.

RESULTS

Increased staining of citrullinated proteins was observed in gingival connective tissue from subjects with periodontitis (80%, 12/15) compared to healthy gingival tissue (27%, 4/15), whereas no differences were observed in gingival epithelium. There was also an increased staining of the citrullinating enzymes PAD2 and PAD4 in gingival connective tissue of patients with periodontitis whereas similar levels of PAD2 and PAD4 were observed in the gingival epithelium of the two groups. Similarly, the mRNA levels of PADI2 and PADI4 were also increased in the gingival tissue of patients with periodontitis compared to healthy controls. Furthermore, presence of P. gingivalis and leukotoxins was comparable in both epithelium and connective tissue, from the different investigated individuals with and without periodontitis, and there were no correlations between the presence of periodontal pathogens and the expression of citrullinated proteins or PAD enzymes.

CONCLUSION

Chronic gingival inflammation is associated with increased local citrullination and PAD2 and PAD4 expression in periodontitis. The increased citrullination and PAD2 and PAD4 expression in periodontitis were, however, independent of the presence of periodontal pathogen P. gingivalis and A. actinomycetemcomitans leukotoxin.

Association between periodontitis and peripheral artery disease: a systematic review and meta-analysis

Background

Inflammation is a common feature of both peripheral arterial disease (PAD) and periodontitis. Some studies have evaluated the association between PAD and periodontitis. However, there is still no specialized meta-analysis that has quantitatively assessed the strength of the association. Thus, we conducted this meta-analysis to critically assess the strength of the association between PAD and periodontitis.

Methods

PubMed, Embase, and the Cochrane Library were searched for observational studies of the association between periodontitis and PAD in February 2018. Risk ratios (RRs) and their 95% confidence intervals (CIs) from included studies were pooled to evaluate the strength of the association between periodontitis and PAD. Weighted mean differences (WMDs) and their 95% CIs were pooled to compare the difference in periodontal-related parameters between PAD and non-PAD patients.

Results

Seven studies including a total of 4307 participants were included in the meta-analysis. The pooled analysis showed that there was a significant difference in the risk of periodontitis between PAD patients and non-PAD participants (RR = 1.70, 95% CI = 1.25–2.29, P = 0.01). There was also a significant difference in number of missing teeth between PAD patients and non-PAD participants (WMD = 3.75, 95% CI = 1.31–6.19, P = 0.003). No significant difference was found in clinical attachment loss between PAD patients and non-PAD participants (WMD = − 0.05, 95% CI = − 0.03–0.19, P = 0.686).

Conclusion

In conclusion, the results of this meta-analysis revealed a significant relationship between periodontitis and PAD. Moreover, our study indicated that PAD patients had more missing teeth than control subjects did. Further high-quality and well-designed studies with specific inclusion and exclusion criteria are required to strengthen the conclusions of this study.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0879-0) contains supplementary material, which is available to authorized users.

Gene expression profiling of periodontitis-affected gingival tissue by spatial transcriptomics

Periodontitis is a highly prevalent chronic inflammatory disease of the periodontium, leading ultimately to tooth loss. In order to characterize the gene expression of periodontitis-affected gingival tissue, we have here simultaneously quantified and localized gene expression in periodontal tissue using spatial transcriptomics, combining RNA sequencing with histological analysis. Our analyses revealed distinct clusters of gene expression, which were identified to correspond to epithelium, inflamed areas of connective tissue, and non-inflamed areas of connective tissue. Moreover, 92 genes were identified as significantly up-regulated in inflamed areas of the gingival connective tissue compared to non-inflamed tissue. Among these, immunoglobulin lambda-like polypeptide 5 (IGLL5), signal sequence receptor subunit 4 (SSR4), marginal zone B and B1 cell specific protein (MZB1), and X-box binding protein 1 (XBP1) were the four most highly up-regulated genes. These genes were also verified as significantly higher expressed in gingival tissue of patients with periodontitis compared to healthy controls, using reverse transcription quantitative polymerase chain reaction. Moreover, the protein expressions of up-regulated genes were verified in gingival biopsies by immunohistochemistry. In summary, in this study, we report distinct gene expression signatures within periodontitis-affected gingival tissue, as well as specific genes that are up-regulated in inflamed areas compared to non-inflamed areas of gingival tissue. The results obtained from this study may add novel information on the genes and cell types contributing to pathogenesis of the chronic inflammatory disease periodontitis.

Development of hydrogels, oleogels, and bigels as local drug delivery systems for periodontitis

Periodontal disease is a chronic inflammation of gum and tissues that surround and support the teeth. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used in the treatment of periodontitis to ease swelling and inflammation. One approach of treating periodontitis is loading the NSAIDs in local drug delivery systems. Therefore, the objective of this study was to investigate the local delivery of the NSAIDs model drug ibuprofen to treat periodontitis using different types of gel formulations (hydrogel, oleogel, and bigel). Gel formulations were characterized in terms of their rheological properties (flow behavior, viscoelastic, and bioadhesive properties) using a controlled-stress rheometer. The in vitro drug release of ibuprofen from gel formulations was investigated using Franz diffusion cells. Gels exhibited more solid-like (elastic) behavior. The viscosity and viscoelastic properties were in the order of oleogel > bigel > hydrogel, respectively. In bioadhesion study, mucin dispersion/plain ibuprofen-hydrogel mixture showed a frequency-dependent interaction of ΔG' = -31 and ΔG' = + 53 Pa at 1 and 10 rad/s, respectively. A strong positive interaction (ΔG' = + 6000 and +130,667 Pa at 1 and 10 rad/s, respectively) was found in mucin dispersion/plain ibuprofen-oleogel mixture. The extent of the negative interaction increased in mucin dispersion/plain ibuprofen-bigel mixture (ΔG' = -59,000 and -79,375 Pa at 1 and 10 rad/s, respectively). After 6 h, ibuprofen release from hydrogel, oleogel, and bigel was 59.5 ± 2.2, 80.6 ± 3.9, and 94.6 ± 3.2%, respectively. Results showed that the rheological and bioadhesive properties and in vitro drug release were influenced by the type of gel formulations.

Membrane Mucin Muc4 promotes blood cell association with tumor cells and mediates efficient metastasis in a mouse model of breast cancer

Mucin-4 (Muc4) is a large cell surface glycoprotein implicated in the protection and lubrication of epithelial structures. Previous studies suggest that aberrantly expressed Muc4 can influence the adhesiveness, proliferation, viability and invasiveness of cultured tumor cells, as well as the growth rate and metastatic efficiency of xenografted tumors. Although it has been suggested that one of the major mechanisms by which Muc4 potentiates tumor progression is via its engagement of the ErbB2/HER2 receptor tyrosine kinase, other mechanisms exist and remain to be delineated. Moreover, the requirement for endogenous Muc4 for tumor growth progression has not been previously explored in the context of gene ablation. To assess the contribution of endogenous Muc4 to mammary tumor growth properties, we first created a genetically engineered mouse line lacking functional Muc4 (Muc4ko), and then crossed these animals with the NDL (Neu DeLetion mutant) model of ErbB2-induced mammary tumorigenesis. We observed that Muc4ko animals are fertile and develop normally, and adult mice exhibit no overt tissue abnormalities. In tumor studies, we observed that although some markers of tumor growth such as vascularity and cyclin D1 expression are suppressed, primary mammary tumors from Muc4ko/NDL female mice exhibit similar latencies and growth rates as Muc4wt/NDL animals. However, the presence of lung metastases is markedly suppressed in Muc4ko/NDL mice. Interestingly, histological analysis of lung lesions from Muc4ko/NDL mice revealed a reduced association of disseminated cells with platelets and white blood cells. Moreover, isolated cells derived from Muc4ko/NDL tumors interact with fewer blood cells when injected directly into the vasculature or diluted into blood from wild type mice. We further observed that blood cells more efficiently promote the viability of non-adherent Muc4wt/NDL cells than Muc4ko/NDL cells. Together, our observations suggest that Muc4 may facilitate metastasis by promoting the association of circulating tumor cells with blood cells to augment tumor cell survival in circulation.

Mucin 4 and matrix metalloproteinase 7 as novel salivary biomarkers for periodontitis

AIM

Periodontitis is a chronic inflammatory disease, characterized by irreversible destruction of tooth-supporting tissue including alveolar bone. We recently reported mucin 4 (MUC4) and matrix metalloproteinase 7 (MMP7) as highly associated with periodontitis in gingival tissue biopsies. The aim of this study was to further investigate the levels of MUC4 and MMP7 in saliva and gingival crevicular fluid (GCF) samples of patients with periodontitis.

MATERIALS AND METHODS

Saliva and GCF samples were collected from periodontitis patients and healthy controls. The levels of MUC4, MMP7, and total protein concentrations were analysed using ELISA or Bradford assay.

RESULTS

MUC4 levels were significantly lower in saliva and GCF from periodontitis patients relative to healthy controls. MMP7 levels were significantly higher in saliva and GCF from periodontitis patients. Multivariate analysis revealed that MUC4 was significantly associated with periodontitis after adjusting for age and smoking habits and, moreover, that the combination of MUC4 and MMP7 accurately discriminated periodontitis from healthy controls.

CONCLUSIONS

MUC4 and MMP7 may be utilized as possible novel biomarkers for periodontitis.

Association between Myocardial Infarction and Periodontitis: A Meta-Analysis of Case-Control Studies

Background and Objective: Many clinical researches have been carried out to investigate the relationship between myocardial infarction (MI) and periodontitis. Despite most of them indicated that the periodontitis may be associated with an increased risk of MI, the findings and study types of these studies have been inconsistent. The goal of this meta-analysis was to critically assess the strength of the association between MI and periodontitis in case-control studies.

Methods: PubMed and the Cochrane Library were searched for eligible case-control studies reporting relevant parameters that compared periodontal status between MI and control subjects. The odds ratios (ORs) and 95% confidence intervals (CIs) from each study were pooled to estimate the strength of the association between MI and periodontitis. The mean differences and 95% CIs for periodontal-related parameters were calculated to determine their overall effects.

Results: Seventeen studies including a total of 3456 MI patients and 3875 non-MI control subjects were included. The pooled OR for the association between MI and periodontitis was 2.531 (95% CI: 1.927–3.324). The mean differences (95% CIs) for clinical attachment loss, probing depth, bleeding on probing, plaque index, and the number of missing teeth were 1.000 (0.726–1.247), 1.209 (0.538–1.880), 0.342 (0.129–0.555), 0.383 (0.205–0.560), and 4.122 (2.012–6.232), respectively.

Conclusion: With the current evidence, the results support the presence of a significant association between MI and periodontitis. Moreover, MI patients had worse periodontal and oral hygiene status and fewer teeth than did control subjects. More high-quality and well-designed studies focusing on the casual relationship between MI and periodontitis should be conducted in the future.

Programmed cell death in periodontitis: recent advances and future perspectives

Periodontitis is a highly prevalent infectious disease, characterized by destruction of the periodontium, and is the main cause of tooth loss. Periodontitis is initiated by periodontal pathogens, while other risk factors including smoking, stress, and systemic diseases aggravate its progression. Periodontitis affects many people worldwide, but the molecular mechanisms by which pathogens and risk factors destroy the periodontium are unclear. Programmed cell death (PCD), different from necrosis, is an active cell death mediated by a cascade of gene expression events and can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. Although PCD is involved in many inflammatory diseases, its correlation with periodontitis is unclear. After reviewing the relevant published articles, we found that apoptosis has indeed been reported to play a role in periodontitis. However, the role of autophagy in periodontitis needs further verification. Additionally, implication of necroptosis or pyroptosis in periodontitis remains unknown. Therefore, we recommend future studies, which will unravel the pivotal role of PCD in periodontitis, allowing us to prevent, diagnose, and treat the disease, as well as predict its outcomes.

Periodontal and inflammatory bowel diseases: Is there evidence of complex pathogenic interactions?

Periodontal disease and inflammatory bowel disease (IBD) are both chronic inflammatory diseases. Their pathogenesis is mediated by a complex interplay between a dysbiotic microbiota and the host immune-inflammatory response, and both are influenced by genetic and environmental factors. This review aimed to provide an overview of the evidence dealing with a possible pathogenic interaction between periodontal disease and IBD. There seems to be an increased prevalence of periodontal disease in patients with IBD when compared to healthy controls, probably due to changes in the oral microbiota and a higher inflammatory response. Moreover, the induction of periodontitis seems to result in gut dysbiosis and altered gut epithelial cell barrier function, which might contribute to the pathogenesis of IBD. Considering the complexity of both periodontal disease and IBD, it is very challenging to understand the possible pathways involved in their coexistence. In conclusion, this review points to a complex pathogenic interaction between periodontal disease and IBD, in which one disease might alter the composition of the microbiota and increase the inflammatory response related to the other. However, we still need more data derived from human studies to confirm results from murine models. Thus, mechanistic studies are definitely warranted to clarify this possible bidirectional association.

Transcriptome sequencing of gingival biopsies from chronic periodontitis patients reveals novel gene expression and splicing patterns

BACKGROUND

Periodontitis is the most common chronic inflammatory disease caused by complex interaction between the microbial biofilm and host immune responses. In the present study, high-throughput RNA sequencing was utilized to systemically and precisely identify gene expression profiles and alternative splicing.

METHODS

The pooled RNAs of 10 gingival tissues from both healthy and periodontitis patients were analyzed by deep sequencing followed by computational annotation and quantification of mRNA structures.

RESULTS

The differential expression analysis designated 400 up-regulated genes in periodontitis tissues especially in the pathways of defense/immunity protein, receptor, protease, and signaling molecules. The top 10 most up-regulated genes were CSF3, MAFA, CR2, GLDC, SAA1, LBP, MME, MMP3, MME-AS1, and SAA4. The 62 down-regulated genes in periodontitis were mainly cytoskeletal and structural proteins. The top 10 most down-regulated genes were SERPINA12, MT4, H19, KRT2, DSC1, PSORS1C2, KRT27, LCE3C, AQ5, and LCE6A. The differential alternative splicing analysis revealed unique transcription variants in periodontitis tissues. The EDB exon was predominantly included in FN1, while exon 2 was mostly skipped in BCL2A1.

CONCLUSIONS

These findings using RNA sequencing provide novel insights into the pathogenesis mechanism of periodontitis in terms of gene expression and alternative splicing.