Gene polymorphism of β-defensin-1 is associated with susceptibility to periodontitis in Japanese

The Impact of IL1B rs1143634 and DEFB1 rs11362 Variants on Periodontitis Risk in Phenylketonuria and Type 1 Diabetes Mellitus Patients in a Latvian Population

OBJECTIVES

Periodontitis is a multifactorial disease that affects approximately 11% of the global population. The objective of this study was to examine whether, among individuals with phenylketonuria and type 1 diabetes mellitus, those with the IL1B rs1143634 and/or DEFB1 rs11362 genetic variants exhibit a higher periodontitis risk compared to healthy controls.

MATERIALS AND METHODS

In all, 43 phenylketonuria patients (aged 12-53), 28 type 1 diabetes mellitus patients (aged 11-40), and 63 healthy controls (aged 12-53) were included. The evaluation of periodontitis risk was conducted using the Silness-Löe plaque index, the Greene-Vermillion index, and an assessment for the necessity of calculus removal. Genetic variants rs1143634 and rs11362 were genotyped from salivary samples using restriction length polymorphism analysis.

RESULTS

The DEFB1 rs11362 variant was associated with higher Silness-Löe and Greene-Vermillion index scores in phenylketonuria patients (p = 0.011 and p = 0.043, respectively). The IL1B rs1143634 variant was associated with lower calculus removal necessity in type 1 diabetes mellitus patients (p = 0.030). Clinical examination showed the worst oral hygiene index scores for PKU patients. PKU patients also reported the least consistent tooth brushing and flossing habits.

CONCLUSIONS

Genetic associations between DEFB1 rs11362 and IL1B rs1143634 variants and oral hygiene indices were observed in the PKU and T1DM groups, suggesting that genetic factors may contribute to periodontal health differences in these populations. Further research with a larger sample size is needed to confirm these findings and develop targeted oral health interventions.

The Genetic Aspects of Periodontitis Pathogenesis and the Regenerative Properties of Stem Cells

Periodontitis (PD) is a prevalent and chronic inflammatory disease with a complex pathogenesis, and it is associated with the presence of specific pathogens, such as Porphyromonas gingivalis. Dysbiosis and dysregulated immune responses ultimately lead to chronic inflammation as well as tooth and alveolar bone loss. Multiple studies have demonstrated that genetic polymorphisms may increase the susceptibility to PD. Furthermore, gene expression is modulated by various epigenetic mechanisms, such as DNA methylation, histone modifications, or the activity of non-coding RNA. These processes can also be induced by PD-associated pathogens. In this review, we try to summarize the genetic processes that are implicated in the pathogenesis of PD. Furthermore, we discuss the use of these mechanisms in diagnosis and therapeutic purposes. Importantly, novel treatment methods that could promote tissue regeneration are greatly needed in PD. In this paper, we also demonstrate current evidence on the potential use of stem cells and extracellular vesicles to stimulate tissue regeneration and suppress inflammation. The understanding of the molecular mechanisms involved in the pathogenesis of PD, as well as the impact of PD-associated bacteria and stem cells in these processes, may enhance future research and ultimately improve long-term treatment outcomes.

Genetic Polymorphism and Gene Expression of β-Defensin-1 in Periodontitis Associated With Type 2 Diabetes Mellitus

Introduction Periodontitis is a multifactorial disease caused by periodontopathic bacteria and influenced by both genetic and environmental factors. Genetic predispositions are found to play a crucial part in the onset and progression of periodontal disease. There is a two-way relationship between diabetes and periodontitis with severe periodontal tissue destruction seen in diabetic patients. Antimicrobial peptide, β-defensin-1 (DEFB1 gene), plays an important role in the innate immune responses and forms the first line of host defense against periodontal pathogens. Single nucleotide polymorphisms (SNPs) in the specific genetic loci of the DEFB1 gene and its expression level could confer a degree of risk or protection from periodontitis associated with diabetes. The present study determined the association between SNPs at the 5' untranslated region (UTR) in the DEFB1 gene and susceptibility to periodontitis associated with type 2 diabetes mellitus (T2DM) and analyzed the effect of 5' UTR polymorphisms on DEFB1 gene expression. Methods SNPs in the 5' UTR of the DEFB1 gene (-20G>A (rs11362), -44C>G (rs1800972), and -52G>A (rs1799946)) were genotyped by polymerase chain reaction (PCR) followed by Sanger sequencing. The study group included periodontitis (n = 40), periodontitis with T2DM (n = 20), and periodontally and systemically healthy as controls (n = 40). DEFB1 gene expression was determined by real-time PCR in the study group comprising periodontitis (n = 20), periodontitis with T2DM (n = 15), and healthy controls (n = 20). The effect of 5' UTR polymorphisms on the expression was analyzed by statistical tools. Results Statistically significant higher prevalence of the variant AA genotype of rs11362 was observed in periodontitis (odds ratio (OR) = 3.64, 95% confidence Interval (CI) = 1.16-11.43, p = 0.04) and periodontitis with T2DM (OR = 5.14, 95% CI = 1.29-20.5, p = 0.03) in comparison with healthy controls. Moreover, there was a significant increase of the variant AA genotype of rs1799946 in periodontitis (OR = 3.88, 95% CI = 1.19-12.68, p = 0.04) compared to healthy controls. DEFB1 gene expression was downregulated in periodontitis and upregulated in periodontitis with T2DM patients when compared to healthy controls but was not statistically significant. No significant association was found for the effect of SNPs of the DEFB1 gene on its expression. Conclusion From the SNP analysis, it can be inferred that the presence of SNPs at the 5' UTR (rs11362 and rs1799946) in the DEFB1 gene may be an important predictive factor for periodontitis.

Targeting hepatocyte growth factor in epithelial-stromal interactions in an in vitro experimental model of human periodontitis

Periodontitis is a chronic inflammatory disease leading to progressive connective tissue degradation and loss of the tooth-supporting bone. Clinical and experimental studies suggest that hepatocyte growth factor (HGF) is involved in the dysregulated fibroblast–epithelial cell interactions in periodontitis. The aim of this study was to explore effects of HGF to impact fibroblast-induced collagen degradation. A patient-derived experimental cell culture model of periodontitis was applied. Primary human epithelial cells and fibroblasts isolated from periodontitis-affected gingiva were co-cultured in a three-dimensional collagen gel. The effects of HGF neutralizing antibody on collagen gel degradation were tested and transcriptome analyses were performed. HGF neutralizing antibody attenuated collagen degradation and elicited expression changes of genes related to extracellular matrix (ECM) and cell adhesion, indicating that HGF signaling inhibition leads to extensive impact on cell–cell and cell–ECM interactions. Our study highlights a potential role of HGF in periodontitis. Antagonizing HGF signaling by a neutralizing antibody may represent a novel approach for periodontitis treatment.

Beta-defensin 1 gene polymorphisms in the pathologies of the oral cavity-Data from meta-analysis: Association only with rs1047031 not with rs1800972, rs1799946, and rs11362

OBJECTIVES

The purpose of this meta-analysis was to reveal a potential association of the four functional polymorphisms in human Beta-defensin 1 (DEFB1) gene: rs1047031(c*5G > A) at 3'UTR and rs11362 (-20 G > A), rs1800972(-44 C > G), and rs1799946 (-52 G > A) at 5'UTR with the risk of common oral cavity pathologies that included periodontitis, caries, lichen planus, and recurrent aphthous stomatitis.

METHODS

The relevant studies were obtained by the two researchers from PubMed, Scopus, and Web of Science up to April 29, 2020. The manual search of the reference lists was also performed. Studies on DEFB1 gene polymorphisms and oral cavity disorders, using the case-control genetic association analysis approach, and published as full texts in English were included. To assess the association strength, odds ratios (ORs) with their 95% confidence intervals (CIs) were extracted.

RESULTS

Thirteen publications met the inclusion criteria and were incorporated in this meta-analysis. Statistically significant values of the association tests were found only for the rs1047031 polymorphism. Allele distribution in the rs1047031 polymorphism was significantly associated with susceptibility to oral cavity pathologies (adjusted P value = 0.003). The rare variant allele carriers had a significantly higher risk for oral disasters under recessive (CC vs CT + TT), and CC vs CT models. No significant correlations between rs11362, rs1800972, and rs1799946 and the risk of oral pathologies were revealed.

CONCLUSIONS

Significant association between rs1047031 polymorphism and risk of oral pathologies has been found, and therefore, we suggest to include this polymorphism in future research concerning the genetic background of the oral cavity diseases.

Association between rs11362 polymorphism in the beta-defensin 1 (DEFB1) gene and dental caries: A meta-analysis

OBJECTIVES

Beta-defensin 1, encoded by the DEFB1 gene, is an important molecule that confers protection from dental caries. Numerous studies have been conducted on the rs11362 polymorphism in the DEFB1 gene. We evaluated the results from studies that have investigated the association between rs11362 polymorphism and dental caries, through a meta-analysis.

METHODS

This meta-analysis was designed according to the PRISMA statement guideline. Electronic databases (PubMed, Web of Science, Scopus, and Cochrane Library) were scanned by two independent researchers. The publication bias was determined by statistical analyses using funnel plot, Egger regression test, and Begg and Mazumdar rank correlation test. Heterogeneity was evaluated using the chi-square test, tau-square, and Higgins I² test. Odds ratio (OR) was used to measure the effect size.

RESULTS

Rank correlation and regression procedures showed the absence of publication bias in the meta-analysis (p > 0.05). The DEFB1 rs11362 polymorphism in the heterozygous (CC vs. CT: OR = 2.20, 95% confidence interval (CI): 1.17, 4.10; p = 0.014) and dominant (CC vs. CT + TT: OR = 3.11, 95% CI: 1.18, 8.21; p = 0.022) models in the permanent dentition subgroup showed significant differences. However, there was no significant difference between any model in either the deciduous dentition (p > 0.05) or the mixed dentition subgroups (p > 0.05).

CONCLUSIONS

This meta-analysis suggests that the DEFB1 rs11362 polymorphism is associated with dental caries in permanent dentition. Moreover, individuals with the TT genotype were found to have seven times higher risk of dental caries than individuals with the CC genotype. There was no such association or statistical difference observed for deciduous and mixed dentitions.

Interactions with the aquaporin 5 gene increase the susceptibility to molar-incisor hypomineralization

OBJECTIVE

The aim of this study was to evaluate whether individual genetic factors involved in amelogenesis, the immune response and water channel proteins may increase the susceptibility to Molar-Incisor Hypomineralization (MIH) in Chinese children.

DESIGN

DNA samples were collected from 86 cases with MIH cases and 344 controls. Sixteen single-nucleotide polymorphisms (SNPs) were investigated. Logistic regression analysis was performed to assess association between SNPs and the risk of MIH.

RESULTS

Our results showed that the risk of MIH in the rs13115627-AA genotype carriers and the rs1784418-TT genotype carriers were significantly higher than that among those with the rs13115627-GG genotype (OR (95 % CI)) = 4.942 (0.658-37.131) and the rs1784418-CT genotype (OR (95 % CI)) = 2.023 (1.63-3.521). The population with the rs1800972-CC genotype and the rs1800972-C allele had a higher risk to develop MIH, OR (95 % CI) = 2.284 (1.267-4.115), OR (95 % CI) = 2.427 (1.493-3.953) respectively. In the Aquaporin 5(AQP5) gene, we individually analyzed two SNPs, rs1996315 and rs923911. We found no significant associations between them and MIH. However, in the analysis of the gene-gene interactions, we discovered a significant two-locus model (P = 0.023) involving rs1996315 and rs923911. Participants with the rs1996315-AG and rs923911-AC genotypes had the highest MIH risk, compared to participants with the rs1996315-GG and rs923911-CC genotypes, OR (95 % CI) = 3.603 (1.147-11.318).

CONCLUSION

This study showed that genetic variants in the AMBN, MMP20 and DEFB1 genes may contribute to MIH in the permanent dentition of children. Moreover, interactions among AQP5 gene may also increase the MIH susceptibility.

DEFB1 rs11362 Polymorphism and Risk of Chronic Periodontitis: A Meta-Analysis of Unadjusted and Adjusted Data

Objective: Chronic periodontitis (CP) is a growing problem that affects the worldwide population, having significant impacts on people's daily lives and economic development. Genetics is an important component in the determination of individual susceptibility to periodontal diseases. Numerous studies have been performed to investigate the association between beta defensin 1 (DEFB1) rs11362 polymorphism and risk of CP, but the results are still inconclusive. Therefore, we conducted this meta-analysis to ascertain whether this variation in DEFB1 is associated with CP susceptibility.

Methods: The relevant studies were searched in PubMed and Chinese National Knowledge Infrastructure (CNKI) databases up to January 9, 2018. Two independent authors selected citations and extracted the data from eligible studies. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were used to assess the strength of the association.

Results: Seven case-control studies were included in this meta-analysis. Based on unadjusted data, there was no obvious association between DEFB1 rs11362 polymorphism and CP risk in all genetic models (A vs. G: OR = 0.86, 95%CI = 0.61–1.20; AA vs. GG: OR = 0.83, 95% CI = 00.50–1.39; AG vs. GG: OR = 1.01, 95%CI = 0.73–1.39; AG+AA vs. GG: OR = 0.91, 95% CI = 00.74–1.11; and AA vs. AG+GG: OR = 0.83, 95% CI = 00.57–1.21); the results of adjusted data also showed no significant relationship. Subgroup analyses based on ethnicity, participants' smoking status, HWE in controls and severity of CP all revealed similar results to that of the overall analysis. Sensitivity analysis indicated the results were robust and no evidence of publication bias was found.

Conclusions: Our meta-analysis suggests that DEFB1 rs11362 polymorphism may not have an important effect on the risk of CP. Further large-scale and well-designed studies are necessary to validate our conclusion in the future.

Identification of genetic risk factors of aggressive periodontitis using genomewide association studies in association with those of chronic periodontitis

To identify the genetic risk factors for aggressive periodontitis (AgP), it is important to understand the progression and pathogenesis of AgP. The purpose of this review was to summarize the genetic risk factors for AgP identified through a case-control genomewide association study (GWAS) and replication study. The initial studies to identify novel AgP risk factors were potentially biased because they relied on previous studies. To overcome this kind of issue, an unbiased GWAS strategy was introduced to identify genetic risk factors for various diseases. Currently, three genes glycosyltransferase 6 domain containing 1 (GLT6D1), defensin α1 and α3 (DEFA1A3), and sialic acid-binding Ig-like lectin 5 (SIGLEC5) that reach the threshold for genomewide significance have been identified as genetic risk factors for AgP through a case-control GWAS.

Human beta defensin-1 is involved in the susceptibility to adeno-tonsillar hypertrophy

INTRODUCTION

Innate immunity molecules are known to play a pivotal role in the homeostasis of the oral mucosa, permitting the presence of commensal microflora and, at the same time, providing a first line of defense against pathogens attempting to invade the oral cavity. Tonsils represent the local immune tissue in oral cavity, being able to provide a non-specific response to pathogens; however, in the presence of microbes or foreign materials present in the mouth tonsils could became infected and develop chronic inflammation, thus leading to hypertrophy. The etiology of the disease is multifactorial depending upon environmental and host factors, the latter including molecules of mucosal innate immunity.

METHODS

Ninety-five children with adeno-tonsillar hypertrophy subjected to adeno-tonsillectomy were recruited at the pediatric otorhinolaryngology service of the Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste (Italy). The specimen discarded from the surgery were used for genomic DNA extraction and genotyping, for mRNA extraction and gene expression analysis, finally the samples were cut and used to prepare slides to perform immunohistochemistry.

RESULTS

Functional polymorphisms within DEFB1 gene, encoding the human beta defensin-1 (hBD-1), were analyzed finding association between DEFB1 rare haplotypes and susceptibility to adeno-tonsillar hypertrophy. DEFB1 mRNA expression was detected in the tonsils and the hBD-1 protein was localized at the epithelia of tonsils mainly in the proximity of the basal lamina.

CONCLUSION

Our findings lead us to hypothesize an involvement of hBD-1 mediated innate immunity in the modulation of the susceptibility towards adeno-tonsillar hypertrophy development.

Spontaneous preterm birth: advances toward the discovery of genetic predisposition

Evidence from family and twin-based studies provide strong support for a significant contribution of maternal and fetal genetics to the timing of parturition and spontaneous preterm birth. However, there has been only modest success in the discovery of genes predisposing to preterm birth, despite increasing sophistication of genetic and genomic technology. In contrast, DNA variants associated with other traits/diseases have been identified. For example, there is overwhelming evidence that suggests that the nature and intensity of an inflammatory response in adults and children are under genetic control. Because inflammation is often invoked as an etiologic factor in spontaneous preterm birth, the question of whether spontaneous preterm birth has a genetic predisposition in the case of pathologic inflammation has been of long-standing interest to investigators. Here, we review various genetic approaches used for the discovery of preterm birth genetic variants in the context of inflammation-associated spontaneous preterm birth. Candidate gene studies have sought genetic variants that regulate inflammation in the mother and fetus; however, the promising findings have often not been replicated. Genome-wide association studies, an approach to the identification of chromosomal loci responsible for complex traits, have also not yielded compelling evidence for DNA variants predisposing to preterm birth. A recent genome-wide association study that included a large number of White women (>40,000) revealed that maternal loci contribute to preterm birth. Although none of these loci harbored genes directly related to innate immunity, the results were replicated. Another approach to identify DNA variants predisposing to preterm birth is whole exome sequencing, which examines the DNA sequence of protein-coding regions of the genome. A recent whole exome sequencing study identified rare mutations in genes encoding for proteins involved in the negative regulation (dampening) of the innate immune response (eg, CARD6, CARD8, NLRP10, NLRP12, NOD2, TLR10) and antimicrobial peptide/proteins (eg, DEFB1, MBL2). These findings support the concept that preterm labor, at least in part, has an inflammatory etiology, which can be induced by pathogens (ie, intraamniotic infection) or "danger signals" (alarmins) released during cellular stress or necrosis (ie, sterile intraamniotic inflammation). These findings support the notion that preterm birth has a polygenic basis that involves rare mutations or damaging variants in multiple genes involved in innate immunity and host defense mechanisms against microbes and their noxious products. An overlap among the whole exome sequencing-identified genes and other inflammatory conditions associated with preterm birth, such as periodontal disease and inflammatory bowel disease, was observed, which suggests a shared genetic substrate for these conditions. We propose that whole exome sequencing, as well as whole genome sequencing, is the most promising approach for the identification of functionally significant genetic variants responsible for spontaneous preterm birth, at least in the context of pathologic inflammation. The identification of genes that contribute to preterm birth by whole exome sequencing, or whole genome sequencing, promises to yield valuable population-specific biomarkers to identify the risk for spontaneous preterm birth and potential strategies to mitigate such a risk.

The antimicrobial peptide, human β-defensin-1, potentiates in vitro osteoclastogenesis via activation of the p44/42 mitogen-activated protein kinases

Previous studies have demonstrated increased expression and raised levels of human β-defensin (hBD)-1 in gingival tissue and crevicular fluid of patients with chronic periodontitis and peri-implantitis, oral bone-resorbing diseases caused by enhanced osteoclastogenesis. Therefore, we aimed to investigate the effect of hBD-1 on osteoclast formation and function and to elucidate the involved signaling pathway in vitro. Human peripheral blood mononuclear cells (PBMCs) were first incubated with various doses of hBD-1 and cell viability was assayed by MTT. PBMCs were treated with macrophage-colony stimulating factor and receptor activator of nuclear factor kappa-B ligand (RANKL) in the presence or absence of non-toxic doses of hBD-1. In vitro osteoclastogenesis was analyzed by tartrate-resistant acid phosphatase (TRAP) staining, osteoclast-specific gene expression, and a resorption pit assay. Involvement of mitogen-activated protein kinases (MAPKs) was studied by immunoblotting and specific MAPK inhibitors. HBD-1 potentiated induction of in vitro osteoclastogenesis by RANKL, as shown by significantly increased number of TRAP-positive multinuclear cells and resorption areas on the dentin slices, and further up-regulated expressions of osteoclast-specific genes compared to those by RANKL treatment (p <0.05). However, hBD-1 treatment without RANKL failed to induce formation of osteoclast-like cells. A significant and further increase in transient phosphorylation of the p44/42 MAPKs was demonstrated by hBD-1 co-treatment (p<0.05), consistent with the inhibitory effect by pretreatment with U0126 or PD98059 on hBD-1-enhanced osteoclastogenesis. Collectively, hBD-1 potentiates the induction of in vitro osteoclastogenesis by RANKL via enhanced phosphorylation of the p44/42 MAPKs.

Caries and Innate Immunity: DEFB1 Gene Polymorphisms and Caries Susceptibility in Genetic Isolates from North-Eastern Italy

Background: The DEFB1 gene, encoding for the constitutively expressed human β-defensin 1 (hBD1) antimicrobial peptide is a potential candidate when studying genetic susceptibility to caries. DEFB1 genetic variations have been reported as contributing to hBD1 production impairment, leading to a greater susceptibility to be infected by oral pathogens, also leading to periodontitis. Methods: We analysed 5 DEFB1 polymorphisms, namely 3 functional single-nucleotide polymorphisms (SNPs) at the 5′-untranslated region (UTR), -52G>A (rs1799946), -44C>G (rs1800972), and -20G>A (rs11362), 2 SNPs at the 3′-UTR, c*5G>A (rs1047031) and c*87A>G (rs1800971) SNP located in potential miRNA binding sites, looking for possible correlations with the risk to develop caries in 654 adult subjects from isolated populations of north-eastern Italy. Dental caries prevalence was evaluated with the DMFT (decayed, missing, filled teeth) index, calculated after an accurate oral examination. DEFB1 SNP genotyping was performed with an Illumina 370k high-density SNP array. Results: Two DEFB1 SNPs were significantly associated with the DMFT index: the strongest association emerged from rs11362 SNP (p = 0.008). In particular G/G homozygous individuals showed a higher DMFT index compared to both G/A heterozygous and A/A homozygous individuals; rs1799946 SNP was also significantly associated with DMFT (p = 0.030), and individuals homozygous for the T allele had a higher DMFT value compared to heterozygous C/T and homozygous C/C individuals. Conclusions: Our study replicated, on a larger number of individuals, previous findings showing the association between two 5′-UTR SNPs in the DEFB1 gene and DMFT, suggesting that these polymorphisms could be considered as potential markers for assessing the risk to develop caries.

P. gingivalis in Periodontal Disease and Atherosclerosis - Scenes of Action for Antimicrobial Peptides and Complement

According to the NHS, it is estimated that over 50% of the adult population are, to some extent, affected by gum disease and approximately 15% of UK population have been diagnosed with severe periodontitis. Periodontitis, a chronic polymicrobial disease of the gums, causes inflammation in its milder form, whereas in its severe form affects the surrounding tissues and can result in tooth loss. During periodontitis, plaque accumulates and sits between the junctional epithelium and the tooth itself, resulting in inflammation and the formation of a periodontal pocket. An interface is formed directly between the subgingival bacteria and the junctional epithelial cells. Bacterial pathogens commonly associated with periodontal disease are, among others, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, together known as the "red complex." This review will mostly concentrate on the role of P. gingivalis, a Gram-negative anaerobic bacterium and one of the major and most studied contributors of this disease. Because periodontal disease is associated with the development of atherosclerosis, it is important to understand the local immune response to P. gingivalis. Innate immune players, in particular, complement and antimicrobial peptides and their effects with regard to P. gingivalis during periodontitis and in the development of atherosclerosis will be presented.