VDR gene polymorphisms, interaction with smoking and risk of periodontal disease in Japanese women: the Kyushu Okinawa maternal and child health study

Polymorphism of salivary proteins and risk of periodontal diseases: A systematic review and meta-analysis of clinical studies

OBJECTIVES

The present systematic review and meta-analysis aimed to assess the association between salivary protein polymorphisms and the risk of periodontal diseases (PD).

DATA

The review incorporated cross-sectional, case-control, retrospective/prospective cohort, and randomized controlled trials assessing the influence of salivary protein polymorphisms on the risk of PD development were included in this review.

SOURCES

A thorough literature search was conducted across electronic databases, namely PubMed, Scopus, Embase, and Web of Science, without any restrictions on publication language and year.

STUDY SELECTION

A total of 168 studies were identified, of which 19 were eligible for inclusion. The risk of bias (RoB) assessment of the included studies was conducted at the methodological level.

RESULTS

A total of 16 studies were included. Polymorphism in the gene encoding TNF-α was found to be protective against gingivitis, while those encoding IL-1α and IL-1β were associated with developing gingivitis. Of the 42 proteins investigated, various gene polymorphisms were identified as protective or risk factors for periodontitis. Protective genes include CFH, DNMT1, OPRM1, and TLR9. Conversely, certain salivary protein genes (e.g., CRP, ERN1, FAM5C, IDH2, LTA, TET2, MPA, NLRP3, TLR4) were associated with periodontitis risk. Notably, IL6, MMP9, and MUC7 genes showed no association with PD, while MMP13 was linked to early implant loss. Overall, the meta-analysis found a statistically significant association between salivary proteins' polymorphisms and risk of PD.

CONCLUSIONS

Salivary protein polymorphisms significantly influence PD, revealing protective and risk-associated genotypes. Despite limitations, findings suggest therapeutic targets, emphasizing the complex genetics-periodontal health interplay.

CLINICAL SIGNIFICANCE

This study unveils salivary protein polymorphisms as pivotal factors in PD. Protective genes including CFH and TLR9, and risk-associated genes including CRP and TLR4, indicate a genetic basis for PD susceptibility.

Influence of Single-Nucleotide Polymorphisms on Vitamin D Receptor Expression in Periodontal Ligament Fibroblasts as a Response to Orthodontic Compression

This study aimed to evaluate if single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene are associated with gene expression in human periodontal ligament (hPDL) fibroblasts under simulated orthodontic compressive force. hPDL samples from 57 patients were used. A physiological compressive strain was performed to simulate orthodontic tooth movement in pressure areas under cell culture conditions. The RNA from hPDL fibroblasts was isolated to determine the relative gene expression (mRNA) of the VDR. The DNA was also isolated for the genotyping analysis of five SNPs in the VDR gene: BglI (rs739837, G/T), BsmI (rs1544410, T/C), ApaI (rs7975232, A/C), FokI (rs2228570, A/G), and TaqI (rs731236, A/G). Real-time polymerase chain reaction was used for both analyses. Kruskal−Wallis tests were used to compare VDR expression among genotypes of each SNP. A linear regression analysis was performed to evaluate SNP−SNP interaction. An established alpha of 5% was used. The relative mRNA VDR expression according to the genotypes in the SNPs BglI, BsmI, ApaI, FokI, and TaqI was not statistically significantly different (p > 0.05). The SNP−SNP interaction evaluated by regression analysis did not demonstrate any statistically significant association. No association was observed (p > 0.05). In conclusion, the SNPs BglI (rs739837), BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570), and TaqI (rs731236) did not show an impact on VDR gene expression in hPDL fibroblasts under simulated orthodontic compressive force.

The relationship between vitamin D receptor gene polymorphisms and periodontitis in turkish individuals with type 2 diabetes mellitus

Background and Aim

Vitamin D receptor (VDR) gene polymorphisms have been implicated in the pathogenesis of many diseases, such as periodontitis and diabetes mellitus (DM). The present study aimed to evaluate the distributions of VDR polymorphisms in diabetic individuals with healthy periodontium (DMH), diabetic individuals with periodontitis (DMP), nondiabetic individuals with healthy periodontium (H), and nondiabetic individuals with periodontitis (P).

Material and Methods

A total of 200 individuals (DMH = 40, DMP = 60, H = 40, and P = 60) were recruited. All clinical periodontal parameters, demographical, and biochemical variables were recorded. Blood samples were collected, and genomic DNA was isolated by Purelink® Genomic DNA Mini Kit. Genotyping of VDR polymorphisms ApaI, BsmI, FokI, and TaqI were determined by real-time polymerase chain reaction (PCR) using allele-specific probes.

Results

The distribution of the BsmI variant showed differences between DMH and H groups (P = 0.034). In addition, carrying the GG genotype (OR = 0.317; 95% CI = 0.126-0.797; P = 0.013) and the G allele (OR = 2.373; 95% CI = 1.203-4.681; P = 0.012) increased the risk of type 2 DM. Moreover, it was determined that the frequency of CC genotype of FokI variant was higher in DMP compared to DMH (P = 0.046). It was determined that having the CC genotype (OR = 2.706; 95% CI = 1.185-6.176; P = 0.017) and the C allele (OR = 1.917; 95% CI = 0.995-3.694; P = 0.049) increased the risk of periodontitis among diabetic individuals. No differences were detected among groups in the genotype and allele distributions of ApaI and TaqI variants (P > 0.05).

Conclusions

The present study showed that the BsmI variant was a risk factor for DM among periodontally healthy individuals and the FokI variant for periodontitis among diabetic individuals.

Vitamin D deficiency is a risk factor for delayed tooth eruption associated with persistent primary tooth

OBJECTIVE

To verify the association between 25(OH)D level and polymorphisms in the vitamin D receptor gene (VDR) with the disturbance in the dental development and eruption.

DESIGN

A total of 183 children from two datasets were evaluated. The first dataset was a case-control (15:15) designed to assess if persistent primary tooth (PPT) is associate with serum 25(OH)D level and with genetic polymorphisms in VDR. The second dataset of genomic DNA samples from 54 children with delayed tooth eruption (DTE) and 99 controls were analysed to verify if genetic polymorphisms in VDR (rs2228570 and rs739837) are associated with DTE. The 25(OH)D and the genotyping/allele distribution were analysed using the T-test and chi-square test, respectively.

RESULTS

The level of 25(OH)D in the PPT group (24.9 ± 6.4 mg/mL) was significantly lower than the control (30.0 ± 7.0 mg/mL) (p=.047). Our data show that children with 25(OH)D deficiency are more likely to present PPT (OR = 2.36; 95%CI: 1.51, 3.70). The rs739837 and rs2228570 polymorphisms were not associated with DTE (OR = 1.44; 95%CI: 0.87, 2.39 and OR = 0.80; 95%CI: 0.45, 1.44, respectively).

CONCLUSIONS

Vitamin D deficiency is a risk factor for PPT.

The role of 25-hydroxyvitamin-D3 and vitamin D receptor gene in human periodontal ligament fibroblasts as response to orthodontic compressive strain: an in vitro study

Background

This study aimed to investigate, if different physiological concentrations of vitamin D (25(OH)D₃) and single nucleotide polymorphisms in vitamin D receptor (VDR) gene have an impact on gene expression in human periodontal ligament (hPDL) fibroblasts induced by simulated orthodontic compressive strain.

Methods

A pool of hPDL fibroblasts was treated in absence or presence of 25(OH)D₃ in 3 different concentrations (10, 40 and 60 ng/ml). In order to evaluate the role of single nucleotide polymorphisms in the VDR gene, hPDL fibroblasts from 9 patients were used and treated in absence or presence of 40 ng/ml 25(OH)D₃. Each experiment was performed with and without simulated orthodontic compressive strain. Real-time PCR was used for gene expression and allelic discrimination analysis. Relative expression of dehydrocholesterol reductase (DHCR7), Sec23 homolog A, amidohydrolase domain containing 1 (AMDHD1), vitamin D 25-hydroxylase (CYP2R1), Hydroxyvitamin D-1-α hydroxylase, receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), cyclooxygenase-2 (COX-2) and interleukin-6 (IL6) was assessed. Three single nucleotide polymorphisms in VDR were genotyped. Parametric or non-parametric tests were used with an alpha of 5%.

Results

RANKL, RANKL:OPG ratio, COX-2, IL-6, DHCR7, CYP2R1 and AMDHD1 were differentially expressed during simulated orthodontic compressive strain (p < 0.05). The RANKL:OPG ratio was downregulated by all concentrations (10 ng/ml, 40 ng/ml and 60 ng/ml) of 25(OH)D₃ (mean = 0.96 ± 0.68, mean = 1.61 ± 0.66 and mean = 1.86 ± 0.78, respectively) in comparison to the control (mean 2.58 ± 1.16) (p < 0.05). CYP2R1 gene expression was statistically modulated by the different 25(OH)D₃ concentrations applied (p = 0.008). Samples from individuals carrying the GG genotype in rs739837 presented lower VDR mRNA expression and samples from individuals carrying the CC genotype in rs7975232 presented higher VDR mRNA expression (p < 0.05).

Conclusions

Simulated orthodontic compressive strain and physiological concentrations of 25(OH)D₃ seem to regulate the expression of orthodontic tooth movement and vitamin-D-related genes in periodontal ligament fibroblasts in the context of orthodontic compressive strain. Our study also suggests that single nucleotide polymorphisms in the VDR gene regulate VDR expression in periodontal ligament fibroblasts in the context of orthodontic compressive strain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01740-8.

The Most Common Vitamin D Receptor Polymorphisms (ApaI,FokI, TaqI, BsmI, and BglI) in Children with Dental Caries: A Systematic Review and Meta-Analysis

Vitamin D participates in the calcification of enamel and dentin and the appropriate immune responses to oral microbial infections. We aimed to assess the association between the most common vitamin D receptor (VDR) polymorphisms (ApaI,FokI, TaqI, BsmI, and BglI) and the risk of dental caries in children.

METHODS

PubMed/MEDLINE, Cochrane Library, Web of Science, and Scopus databases were comprehensively searched until 19 January 2021. Meta-analysis with odds ratios as the effect estimate along with 95% confidence intervals and subgroup analysis were conducted using Review Manager 5.3 software. Publication bias and sensitivity analyses were conducted by Comprehensive Meta-Analysis, version 2.0 software.

RESULTS

Seventy-eight studies were retrieved from the databases, with nine studies included in the final analysis. Based on five genetic models, there was no association between ApaI (rs7975232), TaqI (rs731236), BsmI (rs1544410), FokI (rs2228570), and BglI (rs739837) polymorphisms and susceptibility to dental caries, except for the FokI (rs10735810) polymorphism.

CONCLUSION

Among the VDR polymorphisms considered, an association was found between the FokI (rs10735810) polymorphism and the risk of dental caries, with a protective role of the f allele and ff genotype.

Relationship between vitamin D receptor gene polymorphisms (BsmI, TaqI, ApaI, and FokI) and calcium intake on bone mass in young Japanese women

Background

The high prevalence of low bone mass in young women in Japan has emerged as a serious health issue in recent years. Therefore, the aim of the present study was to reevaluate the relationship between genetic and dietary factors, as well as its influence on bone mass in young Japanese women, with particular emphasis on vitamin D receptor (VDR) gene polymorphisms and calcium intake.

Methods

A total of 499 Japanese women aged 20–24 years were enrolled in the study. The bone mass of the calcaneus was assessed using the quantitative ultrasound method and expressed as the osteo sono-assessment index (OSI). VDR gene polymorphisms (BsmI, TaqI, ApaI, and FokI) were analyzed using DNA extracted from saliva. Calcium intake was assessed using the Food Frequency Questionnaire based on food groups (FFQg) and adjusted with the energy intake. Participants were divided into two groups based on the median calcium intake (250 mg/1000 kcal).

Results

Consequently, bone mass was significantly different among the BsmI and TaqI genotypes after adjusting for body mass index (BMI) (p = 0.030 and 0.019, respectively). In addition, the BsmI AA and ApaI GT genotypes showed significant differences in bone mass between the calcium-intake groups, with low OSI in the low-calcium intake group and high OSI in the high-calcium intake group, respectively, even after adjusting for BMI (p = 0.020 and 0.038, respectively).

Conclusions

These findings may prove instrumental in developing a logical approach towards preventing bone loss in young Japanese women.

Interplay between vitamin D receptor FokI polymorphism and smoking influences Porphyromonas gingivalis proportions in subgingival plaque

AIM

This cross-sectional study investigated the effect of the vitamin D receptor (VDR) FokI polymorphism and its interactions with smoking/drinking on the proportions of periodontal pathogens and periodontitis severity.

MATERIALS AND METHODS

FokI genotyping and bacterial quantification were performed using real-time polymerase chain reaction. Periodontitis severity was determined using mean clinical attachment level (CAL). Regression analyses examined the associations between the FokI polymorphism (rs2228570) and bacterial proportions or periodontitis severity. Effect modification by smoking or drinking was assessed.

RESULTS

The study population comprised 1,460 individuals, aged 39-66 years. After multivariable adjustment, the FokI risk genotypes (CC + CT) were associated with elevated Porphyromonas gingivalis proportions (regression coefficient (β) =0.294 ± 0.139; p = .034) and increased mean CAL (β = 0.130 ± 0.048; p = .007). The effect of the FokI polymorphism on P. gingivalis proportions was greater in smokers (β = 0.897 ± 0.328; p = .006) compared to non-smokers (β = 0.164 ± 0.153; p = .282) and in drinkers (β = 0.668 ± 0.242; p = .006) compared to non-drinkers (β = 0.114 ± 0.169; p = .500). The genotype*smoking interaction for P. gingivalis proportions was significant (p = .043), whereas the genotype*drinking interaction was not (p = .061). Similar results were found for the effect of the genotype*smoking/drinking interaction on mean CAL.

CONCLUSIONS

These findings suggest that the interplay between the host genotype and smoking is important in determining the subgingival microbial composition and periodontitis severity.

Vitamin D Receptor Gene Polymorphisms and Cigarette Smoking Impact on Oral Health: A Case-Control Study

Periodontal diseases are multiperspective problems resulting from numerous and diverse exposures that influence the process of initiation or progression of disease. The negative influence of tobacco smoking on oral health is well documented. The aim of the study was to analyze three SNPs in vitamin D receptor gene-rs7975232 (ApaI), rs2228570 (FokI) and rs1544410 (BsmI)-combined with oral health assessment-pH, gingival index, dry mouth, periodontitis, dry socket, redness of oral cavity mucosa, leukoplakia-in a group of cigarette smokers and in non-smokers. Moreover, the possibility of interactions between these polymorphisms and smoking was examined. When comparing the smokers and non-smokers groups, we noticed that rs1544410 heterozygotes were significantly more frequent in the first group, and for the second, both homozygotes were more frequent. Additionally, we observed the impact of interaction between the rs7975232 genotype and smoking status on gingival index. Current smoking was also associated with all analyzed oral health measures except for leucoplakia. Correlation between pH and age in both smokers and non-smokers was also present. Results of our analysis indicate that in our study group lifestyle and aging were leading factors associated with worse oral health status. However, the impact of genetic variants, and also the impact of their interaction with smoking on analyzed parameters was also visible. These results show great possibilities for all levels of prevention of oral diseases by means of education based on evidence-based medicine, but also for incorporating genetic testing and early interventions into this process for predisposed individuals.

A complete physical mapping of the vitamin D receptor gene for dental implant loss: A pilot study

OBJECTIVES

The aim of this pilot case-control study was to investigate the association of clinical variables and genetic polymorphisms in the vitamin D receptor gene (VDR) with dental implant loss.

MATERIAL AND METHODS

This study was carried out with 244 individuals with mean age 51.90 ± 11.28 (81 cases and 163 controls matched by age, sex, and smoking habit). Also, the clusterization phenomenon was investigated stratifying the sample into two groups: (a) 34 patients with multiple losses (presenting two or more lost implants) and (b) 210 without multiple losses (up to one implant loss). Sociodemographic, clinical, and periodontal parameters were analyzed. The tagSNPs in the VDR gene were analyzed by real-time PCR. Univariate and multivariate analyses were performed (p < .05).

RESULTS

Edentulism, number of implants installed, and Gingival, Plaque, and Calculus Indexes were associated with implant loss in the univariate analysis. After the multivariate analysis, the allele G of rs3782905 in the recessive model, together with number of installed implants and Gingival Index, was associated with implant failure.

CONCLUSION

It is suggested that the allele G of rs3782905 in the recessive model may be a new genetic risk marker for dental implant loss in patients who lost two or more dental implants. In addition, number of implants installed and Gingival Index were also associated. Replication is mandatory to confirm these findings, due to the modest sample size of this work.

Evaluation of Association of Vitamin D Receptor Genetic Polymorphism with Severe Chronic Periodontitis in an Ethnic Tamilian Population

BACKGROUND

Periodontitis is a multifactorial disease characterized by inflammatory responses to increased levels of subgingival pathogens, resulting in connective tissue destruction and alveolar bone loss. The susceptibility of an individual is determined by the complex interplay of the host, genetic, and environmental factors. Vitamin D, a secosteroid hormone, interacts with its nuclear receptor vitamin D receptor (VDR) to regulate crucial biological processes, such as bone metabolism and immune function modulation. Various studies have been conducted in different populations to analyze the association of VDR gene polymorphisms with chronic periodontitis, as these polymorphisms have been demonstrated to play vital roles in the pathogenesis of other diseases.

OBJECTIVE

The aim of the present study was to determine the prevalence and association of the VDR TaqI gene polymorphism with severe chronic periodontitis in an Ethnic Tamilian population.

MATERIALS AND METHODS

A total of 140 subjects were recruited for the study, of which 70 were diagnosed with severe chronic periodontitis and 70 had healthy gums. Each subject's medical and dental histories were taken, and periodontal examinations were performed. Genomic DNA was extracted and genotyping of the VDR gene at the TaqI site was carried out using polymerase chain reaction/restriction fragment length polymorphism. The frequencies of genotypes and alleles were analyzed between the study groups.

RESULTS

The frequency of homozygous TT genotype was 40%, for both the severe chronic periodontitis and the healthy control groups. The distribution of heterozygous Tt genotype was 42.9% in the severe chronic periodontitis group and 47.1% in the healthy control group. The frequency of homozygous tt genotype was 17.1% in the severe chronic periodontitis group and 12.7% in the healthy control group. Although the prevalence of genotype tt and t allele was slightly increased in severe chronic periodontitis patients compared with healthy controls, the frequency of VDR genotype between the study groups was not statistically significant (p-value = 0.751).

CONCLUSION

This present study performed in an Ethnic Tamilian population does not support an association between either of the TaqI alleles within the VDR gene and Severe Chronic Periodontitis.

Association between Single Nucleotide Polymorphisms in Vitamin D Receptor Gene Polymorphisms and Permanent Tooth Caries Susceptibility to Permanent Tooth Caries in Chinese Adolescent

Purpose

Dental caries is a multifactorial infectious disease. In this study, we investigated whether single nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR) gene were associated with susceptibility to permanent tooth caries in Chinese adolescents.

Method

A total of 200 dental caries patients and 200 healthy controls aged 12 years were genotyped for VDR gene polymorphisms using the PCR-restriction fragment length polymorphism (PCR-RFLP) assay. All of them were examined for their oral and dental status with the WHO criteria, and clinical information such as the Decayed Missing Filled Teeth Index (DMFT) was evaluated. Genomic DNA was extracted from the buccal epithelial cells. The four polymorphic SNPs (Bsm I, Taq I, Apa I, and Fok I) in VDR were assessed for both genotypic and phenotypic susceptibilities.

Results

Among the four examined VDR gene polymorphisms, the increased frequency of the CT and CC genotype of the Fok I VDR gene polymorphism was associated with dental caries in 12-year-old adolescent, compared with the controls (X² = 17.813, p ≤ 0.001). Moreover, Fok I polymorphic allele C frequency was significantly increased in the dental caries cases, compared to the controls (X² = 14.144, p ≤ 0.001, OR = 1.730, 95% CI = 1.299–2.303). However, the other three VDR gene polymorphisms (Bsm I, Taq I, and Apa I) showed no statistically significant differences in the caries groups compared with the controls.

Conclusion

VDR-Fok I gene polymorphisms may be associated with susceptibility to permanent tooth caries in Chinese adolescent.

Association Study of Vitamin D Receptor (VDR) - Related Genetic Polymorphisms and their Haplotypes with Chronic Periodontitis in Colombian Population

INTRODUCTION

There is strong evidence that both genetic and environmental factors may affect the periodontal clinical status. However, epidemiological evidence on the association between Vitamin D Receptor (VDR) polymorphisms and Chronic Periodontitis (CP) has been inconsistent.

AIM

The focus of this study was to identify if a possible association between VDR Single-Nucleotide Polymorphisms (SNPs) may be implicated in the aetiopathogenesis of CP in Colombian population.

MATERIALS AND METHODS

One hundred and ten CP patients and 50 Healthy Controls (HC) were recruited. Periodontal status was assessed based on probing depth, clinical attachment level, extent, and severity of periodontal breakdown. The polymerase chain reaction-restriction fragment length polymorphism method was used to identify the VDR rs7975232, rs1544410, rs2228570, and rs731236 SNPs from saliva samples. Odds Ratios (ORs) along with their 95% Confidence Intervals (CIs) were computed to compare the distribution of genotypes/alleles between HC and CP patients, alongside with analysis of Linkage Disequilibrium (LD) and haplotype associations between SNPs. Also, an analysis of the interaction between genetic findings and those significant demographic factors was performed for all SNPs.

RESULTS

There was no association neither between the different genotypes/allele frequencies nor haplotypes and CP. Similarly, no significant differences in extent or severity amongst genotype/allele groups were observed. Even so, interaction analysis revealed significant synergistic interactions between each SNP and age associated with the disease status.

CONCLUSION

Although these results do not support that VDR SNPs could be identified as independent risk predictor variables for CP in the Colombian population, synergistic biological interactive effects of all these SNPs related to age might play a significant role in the pathogenic pathways of CP.

Single nucleotide polymorphisms in the vitamin D pathway associating with circulating concentrations of vitamin D metabolites and non-skeletal health outcomes: Review of genetic association studies

Polymorphisms in genes encoding proteins involved in vitamin D metabolism and transport are recognised to influence vitamin D status. Syntheses of genetic association studies linking these variants to non-skeletal health outcomes are lacking. We therefore conducted a literature review to identify reports of statistically significant associations between single nucleotide polymorphisms (SNP) in 11 vitamin D pathway genes (DHCR7, CYP2R1, CYP3A4, CYP27A1, DBP, LRP2, CUB, CYP27B1, CYP24A1, VDR and RXRA) and non-bone health outcomes and circulating levels of 25-hydroxyvitamin D (25[OH]D and 1,25-dihydroxyvitamin D (1,25[OH]₂D). A total of 120 genetic association studies reported positive associations, of which 44 investigated determinants of circulating 25(OH)D and/or 1,25(OH)₂D concentrations, and 76 investigated determinants of non-skeletal health outcomes. Statistically significant associations were reported for a total of 55 SNP in the 11 genes investigated. There was limited overlap between genetic determinants of vitamin D status and those associated with non-skeletal health outcomes: polymorphisms in DBP, CYP2R1 and DHCR7 were the most frequent to be reported to associate with circulating concentrations of 25(OH)D, while polymorphisms in VDR were most commonly reported to associate with non-skeletal health outcomes, among which infectious and autoimmune diseases were the most represented.

Both 25-hydroxyvitamin-D3 and 1,25-dihydroxyvitamin-D3 reduces inflammatory response in human periodontal ligament cells

Periodontitis is an inflammatory disease leading to the destruction of periodontal tissue. Vitamin D3 is an important hormone involved in the preservation of serum calcium and phosphate levels, regulation of bone metabolism and inflammatory response. Recent studies suggest that vitamin D3 metabolism might play a role in the progression of periodontitis. The aim of the present study was to examine the effects of 25(OH)D3, which is stable form of vitamin D3 in blood, and biologically active form 1,25(OH)2D3 on the production of interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) by cells of periodontal ligament. Commercially available human periodontal ligament fibroblasts (hPdLF) and primary human periodontal ligament cells (hPdLC) were used. Cells were stimulated with either Porphyromonas gingivalis lipopolysaccharide (LPS) or heat-killed P. ginigvalis in the presence or in the absence of 25(OH)D3 or 1,25(OH)2D3 at concentrations of 10-100 nM. Stimulation of cells with either P. gingivalis LPS or heat-killed P. gingivalis resulted in a significant increase of the expression levels of IL-6, IL-8, and MCP-1 in gene as well as in protein levels, measured by qPCR and ELISA, respectively. The production of these pro-inflammatory mediators in hPdLF was significantly inhibited by both 25(OH)D3 and 1,25(OH)2D3 in a dose-dependent manner. In primary hPdLCs, both 25(OH)D3 and 1,25(OH)2D3 inhibited the production of IL-8 and MCP-1 but have no significant effect on the IL-6 production. The effect of both 25(OH)D3 and 1,25(OH)2D3 was abolished by specific knockdown of vitamin D3 receptor by siRNA. Our data suggest that vitamin D3 might play an important role in the modulation of periodontal inflammation via regulation of cytokine production by cells of periodontal ligament. Further studies are required for better understanding of the extents of this anti-inflammatory effect and its involvement in the progression of periodontal disease.