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

Vitamin D binding protein and receptor prevalence in a large population with periodontitis: single nucleotide polymorphism and transcriptomic profiling

BACKGROUND

There is an ongoing controversy regarding the expression of vitamin D receptor (VDR) and binding protein (VDBP) genes, as well as their polymorphisms, in periodontitis. We examined eight single nucleotide polymorphisms (SNPs) and performed a transcriptome-level bioinformatics analysis to clarify their relationship with periodontitis.

METHODS

To explore VDR and VDBP polymorphisms, 600 subjects were included, including 307 patients with chronic periodontitis (CP) and 293 healthy controls. Genomic DNA was extracted from peripheral venous blood collected from each subject. A MassARRAY system was used to detect SNPs, including rs1544410G/A (BsmI), rs2228570C/T (FokI), rs7975232G/T (ApaI), rs731236T/C (TaqI), rs739837G/T, rs9729G/T, and rs3847987C/A in the VDR gene, and rs7041A/C in the VDBP gene. Then, we analyzed transcriptome sequencing datas of gingival tissues from two single-cell transcriptome sequencing studies to identify differential expression profiles. The objective was to further explore the potential association between VDR gene and gingival tissues in individuals with CP.

RESULTS

The regression analysis model revealed a significant relationship between rs739837G/T (P = 0.04) and rs7041A/C (P = 0.03) polymorphisms and CP susceptibility. Subjects carrying the TT genotype of rs739837 showed a decreased risk of developing CP compared to those carrying the GG + GT genotype (OR = 0.53, 95% CI = 0.29-0.99). Individuals carrying the AC + CC genotype of rs7041 showed a reduced risk of developing CP compared to those with the AA genotype (OR = 0.70, 95% CI = 0.51-0.97). Furthermore, allele C of rs7041 was found to have a protective effect against periodontitis (P = 0.03, OR = 0.75, CI = 0.58-0.98). However, no association was found between CP susceptibility and six other 6 SNPs (rs1544410, rs2228570, rs7975232, rs9729, rs731236, and rs3847987). Differential levels of VDR transcription were observed in gingival tissues during CP.

CONCLUSIONS

VDR genetic variability and transcriptional expression are significant factors affecting susceptibility to CP. These findings suggested that rs739837 TT in VDR and rs7041 A/C in VDBP may be protective against periodontitis.

The association between vitamin D receptor gene polymorphism FokI and type 2 diabetic kidney disease and its molecular mechanism: a case control study

BACKGROUND

The role of the vitamin D receptor single nucleotide polymorphism FOKI (VDR-FOKI) (rs2228570) in genetic susceptibility to type 2 diabetic kidney disease (T2DKD) remains uncertain. This study investigated the relationship between VDR-FOKI and T2DKD within the Chinese Plateau Han population and analyzed the underlying mechanisms.

METHODS

A total of 316 subjects were enrolled, including 44 healthy adults, 114 individuals with type 2 diabetes mellitus (T2DM), and 158 patients with T2DKD. According to the 2023 American Diabetes Association Diabetes Guidelines, patients with T2DKD were categorized into low-medium-risk and high-risk groups based on estimates of glomerular filtration rate and urinary albumin-to-creatinine ratio. The VDR-FokI genotypes of all participants were identified using the Taqman probe and classified as homozygous mutant genotypes (C/C or FF), heterozygous mutant genotypes (C/T or Ff), and homozygous wild genotypes (T/T or ff). Plasma levels of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase activity (SOD) were assessed in T2DKD patients with FF and ff genotypes. Additionally, the levels of plasma VDR, GPX4, and P53 were determined using ELISA, while the relative expressions of VDR mRNA, GPX4 mRNA, and TP53 mRNA in whole blood were measured by RT-qPCR.

RESULTS

The T2DM patients with the ff genotype exhibited a 2.93-fold increased likelihood of developing T2DKD compared to those with the FF genotype (ORadjusted = 2.93; 95% CI: 1.142-7.513). Additionally, they were 2.01 times more likely to develop T2DKD than individuals with the FF and Ff genotypes (ORadjusted = 2.01; 95% CI: 1.008-4.006). However, no significant differences in VDR-FokI genotype distribution were observed between the healthy control group and the T2DM group, as well as between the low-medium-risk and high-risk groups of T2DKD. Furthermore, T2DKD patients with the ff genotype had significantly higher plasma levels of MDA compared to those with the FF genotype. In contrast, plasma GSH and SOD content was significantly lower in the ff genotype patients (P < 0.05). Additionally, the GPX4 concentration in ff genotype patients was significantly lower than in FF genotype patients [14.88 (11.32,22.39) vs. 12.76 (8.55,13.75), P = 0.037]. Nevertheless, no statistically significant difference was observed in the expression of VDRmRNA, GPX4mRNA, TP53mRNA, plasma VDR, and plasma P53.

CONCLUSIONS

The ff genotype of VDR-FokI is a risk factor for T2DKD, and the potential mechanism may be related to ferroptosis. However, It is not associated with T2DM or the progression of T2DKD.

Role of vitamin D for orthodontic tooth movement, external apical root resorption, and bone biomarker expression and remodeling: A systematic review

Objective

: This systematic review aimed to evaluate the correlation between vitamin D levels and the rate of tooth movement, external apical root resorption, bone biomarker expression, and bone remodeling.

Methods

: Three databases (PubMed, Scopus, and Web of Science) were systematically searched from inception until 14th March 2023 to identify studies investigating the correlation between orthodontic tooth movement and vitamin D in animals and humans. The quality assessment was made in accordance with the Joanna Briggs Institute Critical Appraisal Checklist.

Results

: Overall, 519 records were identified, and 19 were selected for the qualitative synthesis. Eleven studies investigated the effect of local administration (injections in the periodontal ligament, to the gingiva distal to the teeth, or submucosae palatal area) and systemic administration (oral supplementation) of vitamin D on tooth movement, external apical root movement, pro-inflammatory cytokines, and bone remodeling factors. The remaining eight studies investigated the correlation between serum vitamin D levels and salivary vitamin D levels on bone turnover markers and tooth movement.

Conclusions

: The findings of this systematic review support that vitamin D3 local injections might increase the rate of tooth movement via the receptor activator of the nuclear factor-kB/osteoprotegerin axis. However, the non-uniform study designs and the different protocols and outcome methods make it challenging to draw reliable conclusions.

Sanhuang decoction inhibits autophagy of periodontal ligament fibroblasts during orthodontic tooth movement by activating PI3K-Akt-mTOR pathway

BACKGROUND

Orthodontic tooth movement (OTM) is a typical treatment that corrects malaligned teeth by applying mechanical forces. However, mechanical overload often leads to damage of PDL fibroblasts. Sanhuang decoction (SHD) is commonly used to inhibit inflammation and oxidative stress. However, the mechanism of SHD for OTM treatment is still unclear. Therefore, this study attempts to explore the underlying mechanism through relevant experiments.

METHODS

In the present paper, we established a OTM rat model and further explored the effects of SHD on the PDL of OTM rats. The OTM model and effects of SHD were determined by micro-CT, and the PDL pathological changes, PDL width and capillaries in PDL were observed by H&E staining. Subsequently, the ROS levels in PDL was determined using flow cytometry analysis with DCFH-DA staining, MDA contents and antioxidative enzymes activities were also measured using commercial kits. Furthermore, the autophagy of PDL fibroblasts and proteins in the PI3K/Akt/mTOR pathway were detected using immunoluminescence, qPCR and western blotting assays.

RESULTS

The results showed SHD treatment can alleviate the decrease of PDL cells and capillaries induced by OTM, and improve the MDA and ROS levels in PDL, as well as enhance the activities of SOD and GSH-Px. Further experiments indicated SHD decreased the autophagy levels of PDL fibroblasts via promoting the phosphorylation levels of mTOR, PI3K and Akt proteins.

CONCLUSION

SHD inhibited autophagy of periodontal ligament fibroblasts during orthodontic tooth movement by inhibiting oxidative stress via activating PI3K-Akt-mTOR pathway. Our present findings suggested SHD treatment would be useful for management of the possible disorders occurs in orthodontic tooth movement therapy.

Effect of genetic polymorphisms rs2301113 and rs2057482 in the expression of HIF-1α protein in periodontal ligament fibroblasts subjected to compressive force

OBJECTIVE

Many genes and signaling molecules are involved in orthodontic tooth movement, with mechanically and hypoxically stabilized HIF-1α having been shown to play a decisive role in periodontal ligament signaling during orthodontic tooth movement. Thus, this in vitro study aimed to investigate if genetic polymorphisms in HIF1A (Hypoxia-inducible factor α-subunits) influence the expression pattern of HIF-1α protein during simulated orthodontic compressive pressure.

METHODOLOGY

Samples from human periodontal ligament fibroblasts were used and their DNA was genotyped using real time Polymerase chain reaction for the genetic polymorphisms rs2301113 and rs2057482 in HIF1A . For cell culture and protein expression experiments, six human periodontal ligament fibroblast cell lines were selected based on the patients' genotype. To simulate orthodontic compressive pressure in fibroblasts, a 2 g/cm2 force was applied under cell culture conditions for 48 hours. Protein expression was evaluated by Western Blot. Paired t-tests were used to compare HIF-1α expression with and without compressive pressure application and unpaired t-tests were used to compare expression between the genotypes in rs2057482 and rs2301113 (p<0.05).

RESULTS

The expression of HIF-1α protein was significantly enhanced by compressive pressure application regardless of the genotype (p<0.0001). The genotypes in the genetic polymorphisms rs2301113 and rs2057482 were not associated with HIF-1α protein expression (p>0.05).

CONCLUSIONS

Our study confirms that compressive pressure application enhances HIF-1α protein expression. We could not prove that the genetic polymorphisms in HIF1A affect HIF-1α protein expression by periodontal ligament fibroblasts during simulated orthodontic compressive force.

Editorial of Special Issue "The Role of Vitamin D in Human Health and Diseases 2.0"

Vitamin D performs a differentiating, metabolic and anti-inflammatory function, through genomic, non-genomic and mitochondrial mechanisms of action [...].