Gingival tissue samples from periodontitis patients demonstrate epithelial-mesenchymal transition phenotype

Role of E-cadherin in epithelial barrier dysfunction: implications for bacterial infection, inflammation, and disease pathogenesis

Epithelial barriers serve as critical defense lines against microbial infiltration and maintain tissue homeostasis. E-cadherin, an essential component of adherens junctions, has emerged as a pivotal molecule that secures epithelial homeostasis. Lately, its pleiotropic role beyond barrier function, including its involvement in immune responses, has become more evident. Herein, we delve into the intricate relationship between (dys)regulation of epithelial homeostasis and the versatile functionality of E-cadherin, describing complex mechanisms that underlie barrier integrity and disruption in disease pathogenesis such as bacterial infection and inflammation, among others. Clinical implications of E-cadherin perturbations in host pathophysiology are emphasized; downregulation, proteolytic phenomena, abnormal localization/signaling and aberrant immune reactions are linked with a broad spectrum of pathology beyond infectious diseases. Finally, potential therapeutic interventions that may harness E-cadherin to mitigate barrier-associated tissue damage are explored. Overall, this review highlights the crucial role of E-cadherin in systemic health, offering insights that could pave the way for strategies to reinforce/restore barrier integrity and treat related diseases.

Extracellular vimentin amplifies inflammation: Perspectives for immune injury and therapeutics for periodontitis

Periodontitis is an inflammatory disease triggered by microbial biofilms that promote immune dysfunction and tissue destruction of tooth-supporting tissues. The search for soluble mediators that amplify inflammatory responses and matrix degradation in periodontal tissues has implicated extracellular vimentin (ECV) as a signaling ligand and damage-associated molecular pattern in the pathogenesis of periodontitis. Intracellular vimentin filaments are essential for the structural integrity of cells and the preservation of matrix homeostasis. These are important determinants of health in the periodontium and many other organs. But in inflamed tissues, intracellular vimentin filaments are disassembled. Vimentin is subsequently released from cells into the extracellular space in a soluble form where it drives immune signaling and tissue destruction. We discuss the role of ECV as a signaling molecule in several tissues. We apply these data to understand how in inflammatory diseases like periodontitis, ECV amplifies immune responses that contribute to disease progression. Arising from these data, we consider novel therapeutic opportunities for limiting tissue destruction by targeting ECV for treatment of inflammatory disorders like periodontitis.

Induction of Epithelial-Mesenchymal Transition in Periodontitis Rat Model

OBJECTIVES

 Epithelial-mesenchymal transition (EMT) is a process that shifts cellular phenotype. It is linked to several different inflammatory diseases including periodontitis. This study was conducted to investigate the involvement of the EMT process in an experimental periodontitis (EP) model.

MATERIALS AND METHODS

 Second upper molars of Wistar albino male rats were ligated to induce periodontitis, while controls were not ligated. The animals were sacrificed after 0, 3, 7, 14, and 21 days (n = 6 for each time point). The maxillae were resected, posterior to the incisor teeth, and the gingival tissue surrounding teeth were analyzed. Alveolar bone loss (ABL), epithelial thickness, and the number of inflammatory cells were measured at each time point. Expressions of EMT-related biomarkers (E-cadherin, N-cadherin, Snail1, Twist1, and vimentin) were assessed using the immunohistochemical technique. All experiments were performed in triplicate.

STATISTICAL ANALYSIS

 Inferential comparisons were performed by the kruskall-wallis test. To determine the correlation between the dependent and independent variables ,Spearman's correlation test was used.

RESULTS

 ABL, epithelial thickness, and inflammatory cell count were gradually increased throughout the EP study period. Switching of E-cadherin/N-cadherin was evident and associated with increased nuclear expression of Snail1 and Twist1. Additionally, positive cytoplasmic expression of vimentin was detected from day 7 and increased at subsequent time points. Histoscore of E-cadherin was negatively and significantly correlated with N-cadherin and Snail1. Furthermore, Snail1 and Twist1 histoscores were significantly and positively correlated.

CONCLUSION

 The results demonstrated induction of an EMT phenotype in the EP model. This was supported by cadherin switching and positive vimentin expression along with nuclear translocation of Snail1 and Twist.

E-cadherin Single Nucleotide Variants Are Associated with Increasing Susceptibility to Periodontitis

OBJECTIVES

 To investigate the association of E-cadherin single nucleotide polymorphisms (SNPs) with periodontitis and the potential of these SNPs for identifying susceptibility to periodontitis.

MATERIALS AND METHODS

 Periodontal clinical parameters were recorded followed by collecting venous blood for DNA extraction. Polymerase chain reaction was used to amplify target segments of the E-cadherin gene. Determination of the genotype and allele frequencies was performed using Sanger sequencing. All statistical analyses were performed using GraphPad Prism (version 9) using a statistically significant difference of p < 0.05.

RESULTS

 A total of 207 participants were recruited into two groups of healthy controls (n = 105) and cases diagnosed with periodontitis stage 2 or 3, grade B or C (n = 102). Analyses indicated that the genotypes and alleles of rs3743674 and rs5030625 E-cadherin SNPs were significantly associated with periodontitis. Results from a binary regression model suggested that the presence of these SNPs may indicate susceptibility to periodontitis and increase the rate of progression. Linkage disequilibrium analysis indicated that E-cadherin variants rs3743674 and rs5030625, and rs10272115 and rs16260 were correlated in a nonrandom manner (r 2 = 0.638 and 0.495, respectively).

CONCLUSION

 E-cadherin gene variants, rs3743674 and rs5030625, were associated with the periodontitis phenotype. These biomarkers may identify individuals susceptible to periodontitis and the rate of disease progression.

E-cadherin and TAC in GCF accurately discriminate periodontal health and disease

OBJECTIVE

To investigate the accuracy of gingival crevicular fluid (GCF) E-cadherin and total antioxidant capacity (TAC) to discriminate periodontal health from disease.

SUBJECTS AND METHODS

GCF samples were collected from participants with periodontal health (control), gingivitis, and periodontitis (n = 25 each group). The latter group was further subdivided according to stage (S) and grade. Periodontal parameters were recorded then levels of biomarkers were assayed using ELISA and antioxidant status by use of the Total Antioxidant Capacity Assay for E-cadherin and TAC, respectively.

RESULTS

All periodontal parameters were significantly higher in periodontally diseased groups than controls. The GCF E-cadherin significantly increased in gingivitis and periodontitis (S2 to S4) cases as compared to controls. Level of this protein in GCF samples from periodontitis S3 was significantly higher than in gingivitis and S2 groups. The GCF-TAC level was significantly higher in controls than in periodontally diseased groups. No significant differences were observed in the levels of these proteins between grade B and C periodontitis. Both molecules could discriminate periodontal health from gingivitis and periodontitis stages and differentiating periodontitis S3 from gingivitis and other periodontitis stages.

CONCLUSIONS

Levels of TAC and unbounded E-cadherin in GCF samples exhibited promising diagnostic abilities to differentiate periodontal health and disease.

Ability of gingival crevicular fluid volume, E-cadherin, and total antioxidant capacity levels for predicting outcomes of nonsurgical periodontal therapy for periodontitis patients

OBJECTIVES

To determine the potential of gingival crevicular fluid (GCF) volume, E-cadherin and total antioxidant capacity (TAC) levels to predict the outcomes of nonsurgical periodontal therapy (NSPT) for periodontitis patients.

BACKGROUND

NSPT is the gold-standard treatment for periodontal pockets < 6 mm in depth, however, successful outcomes are not always guaranteed due to several factors. Periodontitis-associated tissue destruction is evidenced by the increased level of soluble E-cadherin and reduced antioxidants in oral fluids which could be used as predictors for success/failure of NSPT.

MATERIALS AND METHODS

Patients with periodontitis (n = 24) were included in this clinical trial and full-mouth periodontal charting was recorded for each patient. GCF samples from periodontal pockets with probing pocket depth (PPD) 4-6 mm from the interproximal surfaces of anterior and premolar teeth were obtained. These sites subsequently received NSPT and were clinically re-evaluated after 1 and 3 months. Levels of GCF E-cadherin and TAC levels were assayed using ELISA.

RESULTS

All clinical periodontal parameters were significantly improved 3 months after completion of NSPT. These outcomes were associated with a significant decrease in E-cadherin levels and GCF volume, while TAC levels were significantly increased in samples obtained in follow-up appointments. Binary regression model analysis showed that PPD, GCF volume, E-cadherin, and TAC levels could significantly (p < .05) predict the outcomes of NSPT. The cut-off points for PPD, GCF volume, E-cadherin and TAC were 5 mm, 4 × 10-3, 1267.97 pg/mL and 0.09 μmol/g, respectively.

CONCLUSION

NSPT improved clinical parameters along with increased antioxidants capacity and epithelial pocket lining integrity. Discrimination of favorable/unfavorable responsiveness of periodontally diseased sites to NSPT could be possible by using GCF volume, PPD, E-cadherin and TAC level assessments.

Interleukin-22 Inhibits Apoptosis of Gingival Epithelial Cells Through TGF-β Signaling Pathway During Periodontitis

Periodontitis is a chronic inflammatory disease characterized by the destruction of tooth-supporting tissues. The gingival epithelium is the first barrier of periodontal tissue against oral pathogens and harmful substances. The structure and function of epithelial lining are essential for maintaining the integrity of the epithelial barrier. Abnormal apoptosis can lead to the decrease of functional keratinocytes and break homeostasis in gingival epithelium. Interleukin-22 is a cytokine that plays an important role in epithelial homeostasis in intestinal epithelium, inducing proliferation and inhibiting apoptosis, but its role in gingival epithelium is poorly understood. In this study, we investigated the effect of interleukin-22 on apoptosis of gingival epithelial cells during periodontitis. Interleukin-22 topical injection and Il22 gene knockout were performed in experimental periodontitis mice. Human gingival epithelial cells were co-cultured with Porphyromonas gingivalis with interleukin-22 treatment. We found that interleukin-22 inhibited apoptosis of gingival epithelial cells during periodontitis in vivo and in vitro, decreasing Bax expression and increasing Bcl-xL expression. As for the underlying mechanisms, we found that interleukin-22 reduced the expression of TGF-β receptor type II and inhibited the phosphorylation of Smad2 in gingival epithelial cells during periodontitis. Blockage of TGF-β receptors attenuated apoptosis induced by Porphyromonas gingivalis and increased Bcl-xL expression stimulated by interleukin-22. These results confirmed the inhibitory effect of interleukin-22 on apoptosis of gingival epithelial cells and revealed the involvement of TGF-β signaling pathway in gingival epithelial cell apoptosis during periodontitis.