Background and Objective Periodontitis is a multifactorial disease that can lead to the progressive destruction of dental support tissue. However, the detailed mechanisms and specific biomarkers involved in periodontitis remain to be further studied. Recently, long non-coding RNAs (lncRNAs) have been found to play a more important role than other types of RNAs. In our study, we analysed the expression of lncRNAs in periodontitis by analysing GSE16134. Material and Methods We identified highly correlated genes by analysing GSE16134 with weighted gene co-expression network analysis (WGCNA) and identified 50 hub lncRNAs that were dysregulated. Then, we used the Linear Models for Microarray Data (Limma) package to identify the hub lncRNAs that were differentially expressed (DElncRNAs). The ceRNA co-expression network data were obtained from several sites, including miRcode, and were used to assess the potential WGCNA function of hub DElncRNAs in periodontitis. Besides, we divided the samples into LBX2-AS1 high and low expression group by the expression level of LBX2-AS1 and calculated DEG by Limma package. Furthermore, we performed GO function, KEGG pathway and GSEA enrichment of DEGs. Results In the analysis, we identified 50 hub lncRNAs that may play important roles in periodontitis. Then, we used the Limma package to identify 3 hub DElncRNAs (LINC00687, LBX2-AS1 and LINC01566). We elucidated the potential function of the hub DElncRNA LBX2-AS1 in periodontitis by constructing a co-expression network of lncRNA-miRNA-mRNA interactions. Totally, 573 DEGs (354 up- and 219 downregulated) in periodontitis samples were identified. DEGs were enriched in different GO terms and pathways, such as neutrophil degranulation, neutrophil activation, neutrophil activation involved in immune response, neutrophil-mediated immunity, antigen processing and presentation, JAK-STAT signalling pathway, natural killer cell-mediated cytotoxicity, EGFR tyrosine kinase inhibitor resistance, phosphatidylinositol signalling system and Vascular Endothelial Growth Factor (VEGF) signalling pathway. Conclusion In our study, we found that 3 hub DElncRNAs (LINC00687, LBX2-AS1 and LINC01566) may be involved in the pathogenesis of periodontitis based on WGCNA and Limma analysis. Our study aimed to elucidate the mechanisms involved in periodontitis at the genetic and epigenetic levels by constructing a ceRNA network associated with lncRNA. Besides, identification DEGs of differential LBX2-AS1 and functional annotation showed that LBX2-AS1 might be associated with periodontitis.
Background and objective Bone remodeling during orthodontic treatment is achieved by the osteogenesis of human periodontal ligament cells (PDLCs) subjected to mechanical loadings. Transcriptional co-activator with PDZ-binding motif (TAZ) mediates bone remodeling in response to extracellular mechanical signals. This study aims to investigate the role of TAZ in osteogenesis of PDLCs under tensile strain. Materials and methods A uniaxial cyclic tensile stress (CTS) at 12% elongation and 6 cycles/min (5 s on and 5 s off) was applied to PDLCs. The osteogenic differentiation was determined by the protein and gene expressions of osteogenic markers using qRT-PCR and Western blot, respectively, and further by alkaline phosphatase (ALP) activity and Alizarin Red S staining. The interaction of TAZ with core-binding factor alpha 1 (Cbf alpha 1) was examined by co-immunoprecipitation. The immunofluorescence histochemistry was used to examine the nucleus aggregation of TAZ and the reorganization of actin filaments. Moreover, small interfering RNA-targeting TAZ (TAZsiRNA) was used for TAZ inhibition and Y-27632 was employed for Ras homologue-associated coiled-coil protein kinase (ROCK) signaling blockage. Results CTS clearly stimulated the nucleus accumulation of TAZ and its interaction with Cbf alpha 1. CTS-induced osteogenesis in PDLCs was significantly abrogated by the infection with TAZsiRNA, as shown by the decreased stained nodules and protein expressions of Cbf alpha 1, collagen type I, osterix, and osteocalcin, along with the inhibition of beta-catenin signaling. Moreover, ROCK inhibition by Y-27632 hindered TAZ nucleus aggregation and its binding with Cbf alpha 1, which subsequently lead to the decreased osteoblastic differentiation of PDLCs. Conclusions Taken together, we propose that TAZ nucleus localization and its interaction with Cbf alpha 1 are essential for the CTS-induced osteogenic differentiation in PDLCs. And such TAZ activation by CTS could be mediated by ROCK signaling, indicating the pivot role of ROCK-TAZ pathway for PDLCs differentiation.
Background and Objectives As a chronic infectious disease, periodontitis could lead to tooth and bone loss. Low-intensity pulsed ultrasound (LIPUS) is a safe, noninvasive treatment method to effectively inhibit inflammation and promote bone differentiation. However, the application of LIPUS in curing periodontitis is still rare. Our study aimed to explore the ability of LIPUS to inhibit inflammatory factors and promote the osteogenic differentiation capacity of human periodontal ligament cells (hPDLCs), and its underlying mechanism. Material and Methods Human periodontal ligament cells were obtained and cultured from the premolar tissue samples for experiments. First, hPDLCs were treated for 24 hours using lipopolysaccharide (LPS) and then exposed to LIPUS (10 mW/cm(2), 30 mW/cm(2), 60 mW/cm(2), and 90 mW/cm(2)) to determine the appropriate intensity to inhibit expression of the inflammatory factors interleukin-6 (IL-6) and interleukin-8 (IL-8) expression. The expression of IL-6 and IL-8 was detected by real-time PCR and enzyme-linked immunosorbent assay. The safety of the most appropriate intensity of LIPUS was tested by a cell counting kit 8 test and an apoptosis assay. Then, LPS-induced hPDLCs were treated in osteogenic medium for 7-21 days with or without LIPUS (90 mW/cm(2), 30 min/d) stimulation. The osteogenic genes RUNX2, OPN, OSX, and OCN were measured by real-time PCR. Additionally, osteogenic differentiation capacity was determined using alkaline phosphatase (ALP) staining, ALP activity analysis, and Alizarin red staining. The activity of the nuclear factor-kappa B (NF-kappa B) signaling pathway was determined by western blotting, real-time PCR, immunofluorescence, and pathway blockade assays. Results Lipopolysaccharide significantly upregulated the production and gene expression of IL-6 and IL-8, while LIPUS stimulation significantly inhibited IL-6 and IL-8 expression in an intensity-dependent manner. LIPUS (90 mW/cm(2)) was chosen as the most appropriate intensity, and there was no detrimental influence on cell proliferation and status with or without osteogenic medium. In addition, consecutive stimulation with LIPUS (90 mW/cm(2)) for 30 min/d for 7 days could also inhibit IL-6 and IL-8 gene expression, upregulate the expression of the osteogenesis-related genes RUNX2, OPN, OSX, and OCN, and promote osteogenic differentiation capacity in osteogenic medium in inflamed hPDLCs. The NF-kappa B signaling pathway was inhibited with LIPUS (90 mW/cm(2)) via inhibition of the phosphorylation of I kappa B alpha and the translocation of p65 into the nucleus in inflamed hPDLCs. Additional investigations of the NF-kappa B inhibitor, BAY 11-7082, revealed that LIPUS (90 mW/cm(2)) acted similarly to BAY 11-7802 to inhibit the NF-kappa B signaling pathway and increase osteogenesis-related genes and promote the osteogenic differentiation capacity of inflamed hPDLCs. Conclusions Low-intensity pulsed ultrasound (90 mW/cm(2)) stimulation could be a safe method to inhibit IL-6 and IL-8 in hPDLCs by inhibiting the NF-kappa B signaling pathway. The effect of LIPUS (90 mW/cm(2)) and BAY 11-7082 on LPS-induced inflammation demonstrated that both of these agents were capable of promoting osteogenesis-related gene expression and osteogenic differentiation in hPDLCs, suggesting that the effect of LIPUS on the promotion of osteogenic activity could be mediated in part through its ability to inhibit the NF-kappa B signal pathway. Hence, LIPUS could be a potential therapeutic method to cure periodontitis.
Background and Objective Periodontitis is a prevalent oral disease responsible for tooth loss. MicroRNAs have been proven crucial in bone disorders over the past decades. Promotive effect on osteogenic activities by microRNA-335-5p (miR-335-5p) has been well demonstrated, but its role involved in the pathogenesis of periodontitis remains elusive. In this study, we established experimental periodontitis (EP) on transgenic mice overexpressing miR-335-5p (335-Tg) to investigate the novel effects of miR-335-5p on periodontal inflammation and bone loss. Methods Experimental periodontitis was established via ligation. The expression of inflammatory and osteoclastic genes was examined by quantitative real-time PCR (qPCR). Morphology of alveolar bone was analyzed by microcomputed tomography (mu CT). Hematoxylin and eosin (H&E), tartrate-resistant acid phosphatase (TRAP), and Toll-like receptor 4 (TLR4) immunohistochemistry (IHC) staining were conducted for histological analysis. Results The expression of miR-335-5p decreased significantly in the periodontal tissues of EP. Compared to the WT-EP group, mu CT analysis showed less bone loss in the 335-Tg-EP group accompanying with a decreased number of TRAP-positive osteoclasts. H&E and IHC staining exhibited attenuated inflammation and TLR4 expression in the 335-Tg-EP group. Furthermore, reduced expressions of IL-1 beta, IL-6, TNF-alpha, and TLR4 were also detected in the 335-Tg-EP group. Overexpression of miR-335-5p in vivo weakened the periodontal bone destruction and inflammation compared with the WT-EP group. Conclusions Our data exhibit novel roles of miR-335-5p in preventing bone loss and inflammation in experimental periodontitis.
Background and objective Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Wnt5a is the activating ligand of the non-canonical Wnt signaling pathways and plays important roles in leukocyte infiltration and cytokine/ chemokine production in inflammatory disorders. Previous studies showed that Wnt5a was significantly up-regulated in gingival tissues of chronic and aggressive periodontitis. However, the roles and the regulatory mechanisms of Wnt5a in peri-implantitis are not well known. Methods The expression of Wnt5a in gingival tissues collected from 8 healthy implant patients and 8 peri-implantitis patients was analyzed by Western blotting and immunofluorescence. Porphyromonas gingivalis infected macrophages isolated from the peripheral blood of healthy volunteers were used as an in vitro cellular model of peri-implantitis. Using neutralizing antibodies, inhibitors and siRNA, the production and roles of Wnt5a in peri-implantitis were assessed by immunofluorescence, quantitative polymerase chain reaction (RT-PCR) and Western blotting. Unpaired two-tailed Student's t test was used to compare qRT-PCR and Western blotting results. P <= .05 was considered statistically significant. Results Wnt5a was highly expressed in the gingival tissues of peri-implantitis patients. Compared to controls, Wnt5a increased in P gingivalis infected macrophages. Wnt5a production in response to P gingivalis infection was dependent on LOX-1 and TLR4. Compared to controls, Wnt5a knockdown impaired IL-1 beta, MCP-1, and MMP2 production induced by P gingivalis infection. Conclusion Our results indicate that Wnt5a is involved in LOX-1 and TLR4 induced inflammatory signature via inflammatory cytokines production in response to P gingivalis infection. These findings demonstrate that Wnt5a maybe an important component of the host immune response in peri-implantitis.
Background Mechanical stimuli can cause periodontal tissue reconstruction. Studies have found that changes in metabolites can be the terminal effect of integrin-mediated mechanical signaling. As a key kinase in integrin regulation, integrin-linked kinase (ILK) mediates mechanical signal transduction, which may contribute to metabolite changes. Defining the components of small-molecule metabolites can optimize mechanical stimuli and periodontal tissue reconstruction. Our purpose is to detect the effect of ILK-mediated mechanical signaling on intracellular small-molecule metabolites (amino acids and organic acids) in human periodontal ligament fibroblasts (HPDLFs). Methods Primary HPDLFs were isolated by enzyme digestion method. Tensile stresses were applied on HPDLFs in vitro using a Flexcell system. ILK gene in HPDLFs was knocked down by RNA interference (RNAi). Twenty common amino acids and seven organic acids in HPDLFs were analyzed by gas chromatography/mass spectrometry technique. Results Five amino acids (ie, alanine, glutamine, glutamate, glycine, and threonine) and three organic acids (ie, pyruvate, lactate, and citric acid) were found to be changed remarkably after mechanical stretching. In addition, baseline levels of four amino acids (ie, glutamate, glutamine, threonine, and glycine) and two organic acids (ie, lactate and citric acid) were significantly different in ILK knockdown compared with wild-type HPDLFs. Conclusion This study suggests that five amino acids (ie, alanine, glutamine, glutamate, glycine, and threonine) and three organic acids (ie, pyruvate, lactate, and citric acid) may act as cellular mediators for mechanical signals in HPDLFs. Among them, four amino acids (ie, glutamate, glutamine, threonine, and glycine) and two organic acids (ie, lactate and citric acid) may be closely linked to ILK.
Objective Our study aimed to elucidate the regulatory molecules related to the osteogenic differentiation of periodontal ligament cells (PDLCs). Background Periodontal ligament cells are a favorable source for cell-based therapy in periodontal bone engineering and regeneration due to their potential multilineage differentiation ability. However, the molecular mechanism and signaling pathways related to the osteogenic differentiation of PDLCs are still unclear. Methods Osteoblast-specific protein expression levels were examined by ELISA in osteogenic-induced PDLCs (induced-PDLC group). A microarray assay and a bioinformatics analysis were carried out to reveal significantly expressed genes and the related pathways in induced-PDLCs, and these findings were then confirmed by qRT-PCR and a luciferase reporter assay. Finally, overexpressing and silencing gene systems were established to identify the specific transcriptional relationship and function of the target genes on the osteogenic differentiation of PDLCs. Results Osteogenically differentiated PDLCs with high levels of osteoblast-specific proteins were established. The upstream stimulatory factor 2 (USF2) and activating transcription factor 4 (ATF4) mRNA levels were upregulated the most through the MAPK signaling pathway in the induced-PDLC group. USF2 could bind to the transcriptional initiation region of ATF4 and regulate its transcriptional activities. Additionally, the overexpression of USF2 promoted osteoblast-specific gene expression and the Alizarin red staining of PDLCs, while simultaneously overexpressing USF2 and silencing ATF4 reversed the favorable osteogenic effect of the induced-PDLCs by reducing osteoblast-specific gene expression and the Alizarin red staining level. Conclusions Our study demonstrated that USF2 could enhance the osteogenic differentiation of PDLCs by regulating ATF4 transcriptional activities, which provides a new strategy to utilize USF2 and ATF4 as potential target molecules for periodontal bone regeneration.
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.
Objective To investigate the molecular mechanism of Progranulin (PGRN) in promoting osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) in inflammatory environment. Background Progranulin is an antagonist of tumor necrosis factor (TNF) receptors (TNFRs) and is known to promote inflammatory periodontal bone defect regeneration. Methods TNFR1- and TNFR2-silenced hPDLSCs designed as hPDLSCs-sh-TNFR1 and hPDLSCs-sh-TNFR2 were cultured with osteoinductive medium containing TNF-alpha and (or) PGRN. Immunofluorescence, quantitative real-time PCR, and western blot were used to, respectively, detect expressions of TNFR1\TNFR2 and osteogenic differentiation markers as well as phosphorylation level in NF-kappa B\MAPK-related pathways. Results Immunofluorescence and real-time PCR showed that TNFR1 and TNFR2 positively expressed in hPDLSCs. TNF-alpha stimulation could significantly decrease the expressions of ALP and RUNX2 in hPDLSCs, whereas PGRN treatment could significantly enhance their expressions, and reverse TNF-alpha-mediated expression suppression of ALP and RUNX2 in hPDLSCs. In hPDLSCs-sh-TNFR1, TNF-alpha mediated osteogenic inhibition decreased, but both TNF-alpha + PGRN and alone PGRN significantly promoted expression of ALP and RUNX2. PGRN significantly enhanced expression of P-ERK1/2 and P-JNK, while corresponding inhibitors eliminated PGRN-stimulated osteogenic differentiation. In hPDLSCs-sh-TNFR2, no significant difference existed in osteogenic markers and P-JNK expression between the PGRN group and the control group. However, PGRN still activated P-ERK1/2 expression. Besides, PGRN antagonized TNF-alpha-enhanced NF-kappa B P65 expression. Conclusion Progranulin promotes osteogenic differentiation of hPDLSCs via TNFR1 to inhibit TNF-alpha-sensitized NF-kappa B and via TNFR2 to activate JNK signaling. The mechanism by which PGRN activates ERK signaling remains to be explored.
Background and objective Oxidative stress has been suggested as an important pathogenic factor contributing to chronic periodontitis with diabetes mellitus (CPDM). Previous studies have revealed the potential therapeutic properties of baicalein (BCI) in oxidative stress-related diseases; however, the antioxidant effects of BCI on therapy for individual with CPDM remain largely unexplored. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in cellular defence against oxidative stress. In this study, we aim to determine whether BCI prevents diabetes-related periodontal tissue destruction by regulating Nrf2 signaling pathway. Material and methods Human gingival epithelial cells (hGECs) were challenged with high glucose (HG, 25 mmol/L) and/or lipopolysaccharide (LPS, 20 mu g/mL). Reactive oxygen species (ROS) were detected by fluorescence-activated cell sorting. The changes of antioxidant-related genes, including Nrf2, catalase (Cat), glutamate-cysteine ligase catalytic subunit (Gclc), superoxide dismutase 1 (Sod1), and superoxide dismutase 2 (Sod2), were quantified by real-time PCR. The localization of phospho-Nrf2 (pNrf2, S40) in the nucleus was detected by immunofluorescence staining and laser scanning confocal microscope (LSCM). PNrf2 and total form of Nrf2 were determined using western blot. The above indicators together with mitochondrial membrane potential (MMP) were further investigated in hGECs pre-treated with different concentrations of BCI (0.01, 0.1, or 0.5 mu g/mL) before stimulated with HG plus LPS (GP). Finally, the role of BCI in activating Nrf2 signaling pathway and relieving the alveolar bone absorption was examined in the CPDM model of Sprague Dawley rats. CPDM rats were oral gavaged with BCI (50, 100, or 200 mg/kg daily). The pNrf2 was detected by immunohistochemistry, and the alveolar bone absorption was examined by microcomputed tomography. Results Our results showed that ROS were significantly increased in both groups of HG and LPS, with the strongest generation in the GP group. In terms of ROS-related gene expression, we found that the mRNA levels of Nrf2, Cat, Gclc, Sod1, and Sod2 were significantly decreased in HG and LPS groups. In consistent with the strongest induction of ROS in GP group, the gene expression in GP group was further decreased as compared to those of HG and LPS groups. Also, the expression of pNrf2 exhibited the same trend with the expression of those antioxidant genes. However, the generation of ROS and the loss of mitochondrial membrane potential induced by GP were abolished by pre-treatment with different concentrations of BCI (0.01, 0.1, or 0.5 mu g/mL). Interestingly, we observed that BCI promoted the nucleus translocation of pNrf2, as well as the gene expression levels of pNrf2 and its target genes (Cat, Gclc, Sod1, and Sod2). Finally, in the CPDM animal model, we found that BCI (at concentrations: 50, 100, and 200 mg/kg) markedly increased the number of pNrf2-positive cells in periodontal tissue and mitigated the alveolar bone loss. Conclusions Our data revealed a potential role for clinic application of BCI under CPDM conditions, suggesting a new therapeutic drug for CPDM patients.
Background and objective CYP1A1 rs1048943 polymorphism was reported to be correlated with periodontitis; however, its association with aggressive periodontitis (AgP) has not yet been investigated. The aim of the study was to investigate the association between the CYP1A1 gene rs1048943 variant with generalized aggressive periodontitis (GAgP) and platelet activation and analyse whether its interaction with hyperlipidemia affects periodontal status in a Chinese population. Methods A case-control study of 224 GAgP patients and 139 healthy controls was conducted. The clinical parameters of probing depth (PD), attachment loss (AL) and bleeding index (BI) were recorded. Platelet count (PLT), platelet distribution width (PDW), platelet large cell ratio (PLCR), mean platelet volume (MPV), serum total cholesterol (TC), triacylglycerol (TG), high and low-density lipoprotein (HDL and LDL) were also measured. The CYP1A1 rs1048943 SNP was genotyped by time-of-flight mass spectrometry. Logistic and linear regression models were used to measure correlation. Results The CYP1A1 rs1048943 AG/GG genotype was associated with GAgP (OR = 1.56, 95%CI: 1.01, 2.42), PD, AL and decreased PDW, PLCR and MPV after adjustment for covariates. Gene-lipid interactions were found between CYP1A1 rs1048943 and HDL for PD (P-interaction = 0.0033), BI (P-interaction = 0.0311) and AL (P-interaction = 0.0141) and between CYP1A1 rs1048943 and LDL for PD (P-interaction = 0.013) among patients with GAgP. Conclusion The G allele of the CYP1A1 rs1048943 gene was associated with GAgP, periodontal status and platelet-related inflammation status in a Chinese population. Hyperlipidemia could modulate the effect of CYP1A1 rs1048943 on the periodontal status of GAgP.
Background and Objective Periodontitis is a bacteria-induced disease that often leads to alveolar bone damage. Its mechanisms were considered to be complicated, involving an imbalance of the formation and resorption of bone. We sought to disclose the antibody-independent function of B cells during periodontitis. Material and Methods Production of receptor activator for nuclear factor-kappa B ligand (RANKL) by total lymphocytes or sorted B-cell subsets in gingiva from healthy or experimental periodontitis animals was examined by flow cytometry, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay. To define the effects of lymphocytes or B-cell subsets on osteoclastogenesis induction, bone marrow mononuclear cells were culture in culture medium of lymphocytes or cocultured with B-cell subsets. Osteoclasts were enumerated by tartrate-resistant acid phosphatase staining. Constituent ratio of B-cell subsets in healthy or experimental periodontitis was also detected by flow cytometry. Result Gingiva B cells produce more RANKL and support more osteoclastogenesis than T and other lymphocytes, and this potential improved in periodontitis. Memory B cells (CD27+CD38-) decreased their percentage in periodontitis. Memory B cells have the highest propensity for RANKL production. Remarkably, memory B cells from periodontitis animals expressed significantly more RANKL compared to healthy controls. Memory B cells supported osteoclast differentiation in vitro in a RANKL-dependent manner, and the number of osteoclasts was higher in cultures with memory B cells from periodontitis animals than in those derived from healthy ones. Other B-cell subsets have limited impact on osteoclast formation. Conclusion Findings of this study further disclose the roles of B cells engaged in periodontal immunomodulation and reveal the considerable importance of memory B cells in alveolar bone homeostasis and their likely contribution to alveolar bone destruction in periodontitis.
Background and ObjectivePeriodontalligament-associated protein-1 (PLAP-1) is an important regulator of osteogenic differentiation ofperiodontalligament cells and plays important role in the homeostasis of periodontal tissues. But the role of PLAP-1 in periodontitis is poorly understood. Expressions of PLAP-1 in experimental periodontitis are observed to elucidate whether PLAP-1 gets involved in the pathogenesis of periodontitis. Material and MethodsWistar rats were randomly allocated to two groups (n=6/group): Ligation group and Control group. PLAP-1 expression in experimental periodontitis was assessed by immunohistochemistry and collagen fibers in periodontal ligament were observed using picrosirius red staining. Expressions of PLAP-1 and CD68 in periodontitis were colocalized by double-labelled immunofluorescence. To further examine the relationship between PLAP-1 and osteoclastogenesis in experimental periodontitis, acute periodontal inflammatory infiltration and alveolar bone destruction were induced by administering ligated rats with 10ng/mL tumor necrosis factor alpha (TNF-; ligation+TNF- group, n=6). Alveolar bone loss was observed by micro-computed tomography (Micro-CT), and osteoclasts were identified by tartrate-resistant acid phosphatase staining (TRAP). Expressions of PLAP-1 in TNF- stimulated human periodontal ligament cells were also detected at 24 and 48hours by western blotting. ResultsPLAP-1 expression levels in periodontal ligament cells and collagen fibers were lower in the ligation group,compared with the control group. Similarly, TNF- decreased PLAP-1 expression in human periodontal ligament cells in vitro. Degradation or destruction of collagen fibers accompanied the reduced PLAP-1 expression in the periodontal ligament in the ligation group. Colocalization of PLAP-1 and CD68 revealedthe positive relationship between PLAP-1 and CD68+ infiltrating cells in periodontitis. More PLAP-1-positive inflammatory cells were found in the ligation+TNF- group, compared with the ligation+saline group. ConclusionPLAP-1-positive inflammatory cells are involved in the pathogenesis of periodontitis. An increase in PLAP-1-positive inflammatory cell number contributes periodontal inflammation and alveolar bone loss.
ObjectiveLiraglutide (LIRA) is a novel antidiabetic therapy that may have anti-inflammatory and bone protective effects. Thus, we studied the potential therapeutic effect of LIRA on periodontitis by assessing the effects of LIRA on the proliferation, migration, inflammation, and osteogenic differentiation of human periodontal ligament cells (hPDLCs) after LPS stimulation. Material and MethodsThe expression of glucagon like-peptide 1 receptor (GLP-1R) was measured using qRT-PCR. HPDLCs proliferation after LIRA were analyzed using MTT assays. Cell migration was quantified using a wound-healing assay. The expression of inflammatory (IL-6 and TNF-) was measured by qRT-PCR and ELISA in hPDLCs. The effect of LIRA on the mineralization potential of hPDLCs was assessed by alizarin red S staining. Furthermore, the expression of Runx2 and ALP was measured by qRT-PCR and Western blot in hPDLCs. ResultsGLP-1R mRNA was present on hPDLCs, and LIRA increased the expression of GLP-1R mRNA. When cultured with 25, 50, 75, 100 and 125 nM LIRA for 24 h, hPDLCs proliferation was enhanced in a dose-dependent manner (P<0.05), and 100 nM was optimal. LIRA promoted hPDLCs migration in a time-dependent manner. LPS significantly increased the expression of IL-6 and TNF- (P<0.01), decreased the formation of mineralization nodes (P<0.01), and inhibited the expression of ALP and Runx2 (P<0.05). LIRA treatment blocked the expression of IL-6 and TNF- (P<0.01), increased the formation of mineralization nodes (P<0.01), and enhanced the expression of ALP and Runx2 (P<0.05). ConclusionLIRA can enhance the proliferation, migration, and osteogenic differentiation of hPDLCs and inhibit the inflammatory response. Thus, LIRA may have potential therapeutic use as an adjuvant treatment for human periodontitis, and this effect is independent of hypoglycemic activity.
The purpose of the meta-analysis was to investigate the potential association of interleukin-10 (IL-10) polymorphisms with susceptibility to chronic periodontitis (CP). A total of 33 studies involving 3487 cases and 4356 controls were identified through a search of multiple electronic databases (last search was updated on 19 July 2018). Three single nucleotide polymorphisms (SNPs) were included in the meta-analysis: -1082A>G(rs1800896), -819C>T(rs1800871), and -592C>A(rs1800872). Odds ratios (ORs) and their 95% confidence intervals (CIs) using allele, dominant, and recessive genetic models were computed to assess the strength of the association. The -1082A>G(rs1800896) polymorphism was found to be associated with decreased CP risk in both Caucasians and Latinos under the dominant model. The -819C>T(rs1800871) and -592C>A(rs1800872) polymorphisms were both associated with increased CP risk in Latinos under the allele and dominant models. In Asians, no associations were observed for any of the polymorphisms under all comparison models. The present meta-analysis suggests that the -1082A>G(rs1800896) polymorphism might be a protective factor for CP in both Caucasians and Latinos, but the -819C>T(rs1800871) and -592C>A(rs1800872) polymorphisms might contribute to CP pathogenesis in Latinos.