NRP1 promotes osteo/odontogenic differentiation via shroom3 in dental pulp stem cells.

Neuropilin-1 (NRP1) is a single transmembrane glycoprotein involved in a variety of physiological events. However, the exact mechanisms by which NRP1 regulates dental pulp stem cells (DPSCs) to differentiate toward an osteo/odontogenic phenotype are poorly understood. Here, we determined the significantly increased expression of full-length NRP1 and glycosaminoglycan (GAG)-modified NRP1 during osteo/odontogenesis in DPSCs. NRP1 was confirmed to promote alkaline phosphatase (ALP) activity, mineralized nodule deposition, protein and mRNA expression of Runx2, DSPP and DMP1 in DPSCs via the loss-of-function and gain-of-function approaches. Further, a non-GAG-modified NRP1 mutant (NRP1 S612A) was generated and the suppression of osteo/odontogenic differentiation was observed in the NRP1 S612A overexpression cells. Knockdown of the adaptor protein shroom3 resulted in the inhibition of osteo/odontogenesis. The protein-protein interaction network, the protein-protein docking and confocal analyses indicated the interactions between NRP1 and shroom3. Furthermore, immunoprecipitation followed by western analysis confirmed the binding of NRP1 to shroom3, but overexpression of NRP1 S612A greatly influenced the recruitment of shroom3 by NRP1. These results provide strong evidence that NRP1 is a critical regulator for osteo/odontogenesis through interacting with shroom3. Moreover, our results indicate that NRP1 S612A attenuates osteo/odontogenesis, suggesting that GAG modification is essential for NRP1 in DPSCs.

Effectiveness of percutaneous balloon compression (PBC) in improving physical function and quality of life in trigeminal neuralgia: a retrospective study.

OBJECTIVE: To evaluate the effectiveness of percutaneous balloon compression (PBC) in treating trigeminal neuralgia (TN) and determine improvements in quality of life (QoL) and daily functional status. METHODS: Data from primary TN (pTN) patients treated with PBC from December 2018 to April 2021 were retrospectively analyzed. Short-Form 36 (SF-36) Health Survey and Functional Independence Measure (FIM) assessments were used to evaluate patients' QoL and physical function every 6 months after surgery, and facial pain was evaluated every 3 to 6 months post-surgery. RESULTS: A total of 80 pTN patients were enrolled for analysis. The Barrow Neurological Institute (BNI) scores of I-II were achieved in 67 (83.8%) patients immediately after the surgery. The estimated rates of BNI I-II pain relief at one, two, and three years were 94.2%, 87.6%, and 83.2%, respectively. All aspects of the SF-36 questionnaire were significantly improved after the PBC, especially in terms of role physical (RP), bodily pain (BP), and social functioning (SF). Patients' functional outcomes measured by FIM at the 6-month follow-up examination were 108.6 ± 9.9, which was significantly improved compared with the pretreatment scores (90.8 ± 12.7). There was no difference between the severity of facial numbness in FIM and any item of the SF-36 except RP (P = 0.004) at 6 months after surgery. There was also no difference in SF-36 and FIM between patients with or without facial hyperalgesia. CONCLUSIONS: PBC can produce long-term and stable pain relief and significantly improve the patient's QoL and physical function. However, further well-designed, high-level, evidence-based studies are needed to precisely assess the efficacy of PBC for pTN patients.

[Regulation mechanism of resveratrol on odontogenic differentiation of human dental pulp stem cells].

PURPOSE: To investigate whether resveratrol promotes odontogenic differentiation of human dental pulp stem cells(DPSCs) by up-regulating the expression of silent information regulator 1 (SIRT1) and activating ß-catenin signaling pathway. METHODS: Different concentrations of resveratrol(0, 10, 15, 20 and 50 µmol/L) were used to treat DPSCs for 7 days and 14 days, and cell proliferative activity was detected by CCK-8. After odontogenic differentiation induced by 15 µmol/L resveratrol for 7 days, alkaline phosphatase(ALP) staining was performed and real-time quantitative reverse transcription PCR(qRT-PCR) was used to detect the mRNA expression of Runt-related transcription factor 2 (Runx2), dentin sialophosphoprotein(DSPP) and dentin matrix protein-1(DMP-1) in DPSCs. Western blot was used to detect the expression of SIRT1 in DPSCs on a specific day (0, 3rd, 5th, 7th and 14th) after differentiation induction. Western blot was also used to detect the expression of SIRT1 and activated ß-catenin during odontogenic differentiation of DPSCs treated by 15 µmol/L resveratrol for 7 days. The experimental data was analyzed with GraphPad Prism 9 software package. RESULTS: 15 µmol/L resveratrol had no significant effect on proliferation of DPSCs on the 7th and 14th day; 15 µmol/L resveratrol promoted odontogenic differentiation of DPSCs and up-regulated mRNA expression of RUNX2, DSPP, and DMP-1 in DPSCs; the expression of SIRT1 was the highest on the 7th day during odontogenic differentiation induction. Resveratrol resulted in the increasing protein expressions of SIRT1 and activated ß-catenin when DPSCs was induced to odontogenic differentiation for 7 days. CONCLUSIONS: Resveratrol promotes odontogenic differentiation of human DPSCs by up-regulating the expression of SIRT1 protein and activating ß-catenin signaling pathway.

Neuropilin 1 (NRP1) Positively Regulates Adipogenic Differentiation in C3H10T1/2 Cells.

Neuropilin 1 (NRP1), a non-tyrosine kinase receptor for several ligands, is highly expressed in many kinds of mesenchymal stem cells (MSCs), but its function is poorly understood. In this study, we explored the roles of full-length NRP1 and glycosaminoglycan (GAG)-modifiable NRP1 in adipogenesis in C3H10T1/2 cells. The expression of full-length NRP1 and GAG-modifiable NRP1 increased during adipogenic differentiation in C3H10T1/2 cells. NRP1 knockdown repressed adipogenesis while decreasing the levels of Akt and ERK1/2 phosphorylation. Moreover, the scaffold protein JIP4 was involved in adipogenesis in C3H10T1/2 cells by interacting with NRP1. Furthermore, overexpression of non-GAG-modifiable NRP1 mutant (S612A) greatly promoted adipogenic differentiation, accompanied by upregulation of the phosphorylated Akt and ERK1/2. Taken together, these results indicate that NRP1 is a key regulator that promotes adipogenesis in C3H10T1/2 cells by interacting with JIP4 and activating the Akt and ERK1/2 pathway. Non-GAG-modifiable NRP1 mutant (S612A) accelerates the process of adipogenic differentiation, suggesting that GAG glycosylation is a negative post-translational modification of NRP1 in adipogenic differentiation.

Decompression versus decompression plus fusion for treating degenerative lumbar spinal stenosis: A systematic review and meta-analysis.

BACKGROUND: Degenerative lumbar spinal stenosis (DLSS) is a complex clinical syndrome that leads to spinal compression. Decompression with fusion has been the most commonly used surgical procedure for treating DLSS symptoms for many years. However, the exact role of fusion and its effectiveness in DLSS therapy has recently been debated. OBJECTIVE: The main purpose of this study was to compare the efficacy and safety of decompression alone and decompression plus fusion in the treatment of DLSS with or without spondylolisthesis. STUDY DESIGN: A systematic review and meta-analysis of the therapeutic effects of decompression for DLSS with or without the combination of fusion. METHODS: A literature search in five relevant databases, including Web of Science, PubMed, Embase, Medline, and Cochrane Library was performed from the inception of the database to March 2022. Only randomized controlled trials (RCTs) assessing the comparison between decompression and decompression plus fusion for DLSS were included. RESULTS: A total of seven studies, 894 patients were analyzed in this meta-analysis. Among these, 443 patients were included in the decompression plus fusion group while 451 patients were included in the decompression alone group. Pooled analysis showed that the combination of decompression with fusion had no superior benefits to decompression alone in terms of Oswestry Disability Index (ODI) score in the first 2 years and long-term follow-up after surgery, also no significant difference in the improvement of back and leg pain was found between two groups. Adding fusion to decompression was associated with a longer operation time, higher complication rate, more blood loss, and extended hospital stay. Furthermore, there was no difference in reoperation rates and patients' satisfaction between the two groups at the last follow-up. CONCLUSION: Decompression plus fusion may not be associated with a better clinical outcome in ODI scores and back or leg pain improvement but with a longer duration of operation time, extended hospital stay, and more blood loss.

Histone Demethylase Jmjd3 Regulates the Osteogenic Differentiation and Cytokine Expressions of Periodontal Ligament Cells.

Periodontal ligament (PDL) cells are critical for the bone remodeling process in periapical lesions since they can differentiate into osteoblasts and secrete osteoclastogenesis-promoting cytokines. Post-translational histone modifications including alterations of the methylation status of H3K27 are involved in cell differentiation and inflammatory reaction. The histone demethylase Jumonji domain-containing 3 (Jmjd3) specifically removes methylation of H3K27. We investigated whether Jmjd3 is involved in the osteogenic differentiation and secretion of PDL cells' inflammatory factors. Jmjd3 expression in periapical lesions was examined by immunostaining. Using siRNA specific for Jmjd3 or the specific Jmjd3 inhibitor GSK-J4, we determined Jmjd3's roles in osteogenic differentiation and cytokine production by real-time RT-PCR. The locations of Jmjd3 and NF-κB were analyzed by immunocytochemistry. Compared to healthy PDLs, the periapical lesion samples showed higher Jmjd3 expression. Treatment with GSK-J4 or Jmjd3 siRNA suppressed PDL cells' osteogenic differentiation by suppressing the expressions of bone-related genes (Runx2, Osterix, and osteocalcin) and mineralization. Jmjd3 knockdown decreased the expressions of cytokines (TNF-α, IL-1ß, and IL-6) induced by lipopolysaccharide extracted from Porphyromonas endodontalis (Pe-LPS). Pe-LPS induced the nuclear translocations of Jmjd3 and NF-κB; the latter was inhibited by GSK-J4 treatment. Jmjd3 appears to regulate PDL cells' osteogenic differentiation and proinflammatory cytokine expressions.

Vestigial-Like 3 Plays an Important Role in Osteoblast Differentiation by Regulating the Expression of Osteogenic Transcription Factors and BMP Signaling.

Our previous gene profiling analysis showed that the transcription cofactor vestigial-like 3 (VGLL3) gene expression was upregulated by mechanical tension in the mouse cranial suture, coinciding with accelerated osteoblast differentiation. Therefore, we hypothesized that VGLL3 plays a significant role in osteogenic differentiation. To clarify the function of VGLL3 in osteoblasts, we examined its expression characteristics in mouse bone tissue and the osteoblastic cell line MC3T3-E1. We further examined the effects of Vgll3 knockdown on osteoblast differentiation and bone morphogenetic protein (BMP) signaling. In the mouse cranial suture, where membranous ossification occurs, VGLL3 was immunohistochemically detected mostly in the nucleus of osteoblasts, preosteoblasts, and fibroblastic cells. VGLL3 expression in MC3T3-E1 cells was transient and peaked at a relatively early stage of differentiation. RNA sequencing revealed that downregulated genes in Vgll3-knockdown cells were enriched in gene ontology terms associated with osteoblast differentiation. Interestingly, most of the upregulated genes were related to cell division. Targeted Vgll3 knockdown markedly suppressed the expression of major osteogenic transcription factors (Runx2, Sp7/osterix, and Dlx5) and osteoblast differentiation. It also attenuated BMP signaling; moreover, exogenous BMP2 partially restore osteogenic transcription factors' expression in Vgll3-knockdown cells. Furthermore, overexpression of Vgll3 increased the expression of osteogenic transcription factors. These results suggest that VGLL3 plays a critical role in promoting osteoblast differentiation and that part of the process is mediated by BMP signaling. Further elucidation of VGLL3 function will increase our understanding of osteogenesis and skeletal disease etiology.

Changes of Serum Homocysteine and Vitamin B12, but Not Folate Are Correlated With Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis of Case-Control Studies.

Background: Obsessive-compulsive disorder (OCD) a complex neuropsychiatric disorder, is characterized by irresistible obsessive thinking and compulsive behavior. Folate is a member of water-soluble vitamins in the human body and sustains many normal daily activities (e.g., exercise, sleep, and memory). Homocysteine, a sulfur-containing non-essential amino acid, has been investigated in numerous psychiatric disorders (e.g., OCD). Vitamin B12 is a type of complex organic compound with cobalt contained. Moreover, vitamin B12 and folate deficiency and high levels of homocysteine were found to have an effect on brain functions and also lead to non-specific psychiatric symptoms. Objectives: This study aimed to confirm the epidemiological evidence of OCD and investigate whether vitamin B12, folate, and homocysteine have an effect on the etiology of OCD. Methods: A systematic search was conducted on eight databases (i.e., PubMed, Embase, Web of Science, the Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database), and the retrieval time was up to March 2021. The available articles involving patients with OCD with/without abnormal serum levels of vitamin B12, folate, and homocysteine were comprehensively reviewed and analyzed. Results: A total of 5 studies involving 309 patients were included in this meta-analysis, including 172 cases in the experimental group and 137 in the control group. The content of folate in the OCD group was not significantly different from that in the control group (SMD = -0.089, 95%CI -0.755 to 0.577, p = 0.794). And serum homocysteine was significantly higher in the patients with OCD (SMD = 1.132, 95%CI 0.486 to 1.778, p = 0.001). Vitamin B12 was significantly lower in patients with OCD (SMD = -0.583, 95%CI -0.938 to -0.229, p = 0.001). Conclusions: This meta-analysis shows serum high levels of homocysteine, low levels of vitamin B12, and normal folate level are closely correlated with OCD. However, high-quality case-control studies should be further conducted to explore the correlation between serum levels of vitamin B12, folate, homocysteine, and OCD. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021262161; PROSPERO (Number CRD#42021262161).

[Effect of inhibition of Porphyromonas endodontalis on osteoblast differentiation].

PURPOSE: Porphyromonas endodontalis (P.e) is the dominant bacterium in the infected canal of pulpal and periapical disease.Lipopolysaccharides (LPS) in the outer membrane of the cell wall is an important toxicity factor of P.e. In this study, the effect of P.e-LPS on osteoblast differentiation was studied, and the pathogenic mechanism of P.e-LPS in periapical bone resorption disease was explored. METHODS: Porphyromonas endodontalis was cultured under anaerobic conditions. P.e-LPS was extracted by thermophenol water method, and then the extracted LPS was qualitatively analyzed by gel limulireagent method. Preosteoblast cell line MC3T3-E1 were induced to differentiate into osteoblasts by osteoblast differentiation medium (50 µg/mL ascorbic acid，6 mmol/L beta-glycerphosphate). Expressions of osteogenic differentiation genes including distal-less homeobox 5（DLX5）, runt-related transcription factor 2(Runx2), Osterix, bone sialoprotein (BSP), OCN(osteocalcin) and Collagen were detected by RT-PCR. The activity of alkaline phosphatase(ALP)， alizarin red staining and Von Kossa staining were used to determine the mineralization level of osteoblasts.The expression of TOLL-like receptor-4 (TLR-4), the receptor of P.e-LPS, was silenced by siRNA transfection. SPSS 11.0 software package was used for statistical analysis of the data. RESULTS: The mRNA expressions of osteogenic differentiation genes including DLX5, Runx2, Osterix, OCN, BSP, and Collagen were significantly decreased after treated with P.e-LPS (10 µg/mL) for 3 d, compared with the control group（P<0.05）.After treated with P.e-LPS (10 µg/mL) for 7 d or 14 d, respectively, ALP and alizarin red staining intensity was decreased. P.e-LPS was applied to the si-TLR-4 transfection group and the control group for 7,14 and 21 d, respectively. Compared with the control group, the expression level of osteogenic differentiation genes, ALP, alizarin red staining and Von Kossa staining intensity of si-TLR-4 group were significantly higher than those of the control group (P<0.05). CONCLUSIONS: P.e-LPS inhibits the differentiation of osteoblasts through TLR-4 receptor, thus participating in bone resorption process of periapical lesions.

[Resveratrol suppressed the expression of MIP-2 induced by lipopolysaccharide in osteoblasts via up-regulating SOCS-3].

PURPOSE: To explore whether resveratrol dependents on the production of suppressor of cytokine signaling suppressor 3 (SOCS-3) in inhibiting mRNA production of macrophage inflammatory protein-2 (MIP-2) in osteoblasts induced by lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e). METHODS: MC3T3-E1 cells were treated with different concentrations of resveratrol (0, 5, 10 and 20 µmol/L) and 20 µmol/L resveratrol for different time( 0, 10, 30, 60, 120 and 180 min). The expression of SOCS-3 protein was detected by Western blot. MC3T3-E1 cells were transfected with mouse SOCS3 siRNA (si-SOCS-3) and control siRNA(si-control). Reverse transcription real-time PCR(real-time RT-PCR) and Western blot was used to detect the silencing efficiency of SOCS-3. Cells were stimulated by 20 µg/mL P.e-LPS for 24 h after transfection, in the absence or presence of 20 µmol/L resveratrol for 1 h , and the changes of MIP-2 mRNA were determined by real-time RT-PCR. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. RESULTS: Treatment of MC3T3-El cells with different concentrations of resveratrol caused a significant increase in SOCS-3 protein expression in a dose-dependent manner. During the observation time of 180 min, SOCS-3 protein expression was the highest at 20 µmol/L resveratrol-treated osteoblasts for 60 min. The silencing efficiency of SOCS-3 mRNA was 63.7%. Transfection with SOCS-3 siRNA increased MIP-2 mRNA expression in LPS-stimulated MC3T3-E1 cells and negated the inhibitory effects of resveratrol on LPS-induced MIP-2 mRNA expression(P<0.05). CONCLUSIONS: Resveratrol inhibits the expression of MIP-2 mRNA in osteoblasts induced by P.e-LPS by up-regulating the expression of SOCS-3 protein.

Extracellular vesicles of P. gingivalis-infected macrophages induce lung injury.

Periodontal diseases are common inflammatory diseases that are induced by infection with periodontal bacteria such as Porphyromonas gingivalis (Pg). The association between periodontal diseases and many types of systemic diseases has been demonstrated; the term "periodontal medicine" is used to describe how periodontal infection/inflammation may impact extraoral health. However, the molecular mechanisms by which the factors produced in the oral cavity reach multiple distant organs and impact general health have not been elucidated. Extracellular vesicles (EVs) are nano-sized spherical structures secreted by various types of cells into the tissue microenvironment, and influence pathophysiological conditions by delivering their cargo. However, a detailed understanding of the effect of EVs on periodontal medicine is lacking. In this study, we investigated whether EVs derived from Pg-infected macrophages reach distant organs in mice and influence the pathophysiological status. EVs were isolated from human macrophages, THP-1 cells, infected with Pg. We observed that EVs from Pg-infected THP-1 cells (Pg-inf EVs) contained abundant core histone proteins such as histone H3 and translocated to the lungs, liver, and kidneys of mice. Pg-inf EVs also induced pulmonary injury, including edema, vascular congestion, inflammation, and collagen deposition causing alveoli destruction. The Pg-inf EVs or the recombinant histone H3 activated the NF-κB pathway, leading to increase in the levels of pro-inflammatory cytokines in human lung epithelial A549 cells. Our results suggest a possible mechanism by which EVs produced in periodontal diseases contribute to the progression of periodontal medicine.

Histone demethylase Jmjd3 modulates osteoblast apoptosis induced by tumor necrosis factor-alpha through directly targeting RASSF5.

Purpose: Regulation of gene expression is fine-tuned by a dynamic equilibrium between repressive modifications and transcriptional activation of histone tails. Jumonji domain-containing 3 (Jmjd3), also known as KDM6B, is a specific histone demethylase for trimethylation on histone H3 lysine 27 (H3K27me3) that specifically removes the methylation of H3K27me3 and promotes gene expression. Our previous study showed that Jmjd3 inhibits serum deprivation-induced osteoblast apoptosis. In this study, we clarified the role of Jmjd3 in tumor necrosis factor-alpha (TNF-α)-induced osteoblast apoptosis. Materials and Methods: Jmjd3 activity was inhibited by GSK-J4. Transfection of osteoblastic murine MC3T3-E1 cells with short hairpin RNA (shRNA) was used to establish stable Jmjd3 knockdown cells. Osteoblast apoptosis was detected using Annexin V-APC/PI staining, cysteinyl aspartate specific protease-3 (caspase-3) activity assays, and Western blot. Real-time polymerase chain reaction (PCR) and chromatin immunoprecipitation (ChIP) assays were performed to clarify the mechanism responsible for Jmjd3-regulated osteoblast apoptosis induced by TNF-α. Results: Based on Annexin V-APC/PI staining, caspase-3 activation, and poly ADP-ribose polymerase (PARP) cleavage, pretreatment with GSK-J4 and knockdown of Jmjd3 by shRNA transfection each inhibited osteoblast apoptosis. Furthermore, knockdown of Jmjd3 decreased the expression of Ras association domain family 5 (RASSF5), which is a pro-apoptotic gene of the Ras associated domain family. H3K27me3 levels in the promoter region of RASSF5 were up-regulated in the Jmjd3 knockdown cells. Conclusions: Jmjd3 regulated TNF-α-induced osteoblast apoptosis by targeting RASSF5.

[Resveratrol counteracts lipopolisaccharide-mediated oxidative stress by upregulating SOCS-1 production].

PURPOSE: To investigate the protective effect and mechanism of resveratrol on oxidative stress of MC3T3-E1. METHODS: The levels of reactive oxygen species in the cells were observed by fluorescence microscope and flow cytometry. The expression of SOCS-1 protein was detected by Western blot. SOCS-1 transient transfected cell line was established, and the levels of reactive oxygen species in transfected cells were observed by fluorescence microscopy and flow cytometry. The data were analyzed using SPSS22.0 software package. RESULTS: The level of ROS in LPS group was significantly higher than that in the blank group and LPS+RES group (P<0.05). The expression level of SOCS-1 protein was increased after LPS stimulation for 30 min (P<0.05). The level of ROS in the siSOCS-1+LPS+RES group was significantly higher than that in the untransfected group (P<0.05). CONCLUSIONS: Resveratrol may counteract LPS-mediated oxidative stress in MC3T3E1 cells by modulating SOCS-1 protein.

[Effect of resveratrol on the expression of MIP-2 in P.e-LPS-induced mouse osteoblasts].

PURPOSE: To investigate the effect of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of macrophage inflammatory protein-2 (MIP-2) mRNA and protein levels in MC3T3-E1 cells and the influence of resveratrol on the expression of MIP-2 protein in P.e-LPS induced cells. METHODS: MC3T3-E1 cells were treated with different concentrations of P.e-LPS(0-50 mg/L) and 20 mg/L P.e-LPS for different time (0-48 h). The expression of MIP-2 mRNA and protein was detected by real-time RT-PCR and enzyme linked immunosorbent assay (ELISA). MC3T3-E1 cells were pretreated with resveratrol for 1 h in the presence of 20 mg/L P.e-LPS for 24 h，which was detected by ELISA. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. RESULTS: Treatment of MC3T3-El cells with different concentrations of P.e-LPS(0-50 mg/L) caused a significantly increase in MIP-2 mRNA and protein expression in dose-dependent manners.The expression of MIP-2 protein increased from (41.86±2.49) ng/L to (3126.74±158.30) ng/L, and the difference was significant(P<0.05). In the observation time (0-48 h), the impact of 20 mg/L P.e-LPS on induction of MIP-2 in MC3T3-El cells exhibited a time-dependent manner. At 48 h, the maximal induction of MIP-2 protein expression was (2102.55±123.27) ng/L(P<0.01). Incubation of cells with 10 µmol/L resveratrol for 1h significantly decreased the expression of MIP-2 protein from (1805.33±67.54) ng/L to（813.82±47.21) ng/L, and the difference was significant(P<0.05). CONCLUSIONS: The results suggest that P.e-LPS may mediate MIP-2 expression in MC3T3-E1 cells, and resveratrol has a significant inhibitory effect on this process.

Resveratrol Suppresses Matrix Metalloproteinase-2 Activation Induced by Lipopolysaccharide in Mouse Osteoblasts via Interactions with AMP-Activated Protein Kinase and Suppressor of Cytokine Signaling 1.

Porphyromonas endodontalis (P. endodontalis) lipopolysaccharide (LPS) is associated with the progression of bone resorption in periodontal and periapical diseases. Matrix metalloproteinase-2 (MMP-2) expression and activity are elevated in apical periodontitis and have been suggested to participate in bone resorption. Therefore, inhibiting MMP-2 activation may be considered a therapeutic strategy for treating apical periodontitis. Resveratrol is a natural non-flavonoid polyphenol that has been reported to have antioxidant, anti-cancer, and anti-inflammatory properties. However, the capacity of resveratrol to protect osteoblast cells from P. endodontalis LPS insults and the mechanism of its inhibitory effects on MMP-2 activation is poorly understood. Here, we demonstrate that cell viability is unchanged when 10 mg L-1P. endodontalis LPS is used, and MMP-2 expression is drastically induced by P. endodontalis LPS in a concentration- and time-dependent manner. Twenty micromolar resveratrol did not reduce MC3T3-E1 cell viability. Resveratrol increased AMP-activated protein kinase (AMPK) phosphorylation, and Compound C, a specific AMPK inhibitor, partially abolished the resveratrol-mediated phosphorylation of AMPK. In addition, AMPK inhibition blocked the effects of resveratrol on MMP-2 expression and activity in LPS-induced MC3T3-E1 cells. Treatment with resveratrol also induced suppressor of cytokine signaling 1 (SOCS1) expression in MC3T3-E1 cells. SOCS1 siRNA negated the inhibitory effects of resveratrol on LPS-induced MMP-2 production. Additionally, resveratrol-induced SOCS1 upregulation was reduced by treatment with compound C. These results demonstrate that AMPK and SOCS1 activation are important signaling events during resveratrol-mediated inhibition of MMP-2 production in response to LPS in MC3T3-E1 cells, and there is crosstalk between AMPK and SOCS1 signaling.

[Effects of Porphyromonas endodontalis lipopolysaccharides on the expression of monocyte chemotactic protein-1 in mouse osteoblasts].

PURPOSE: To investigate the effects of lipopolysaccharide (LPS) extracted from Porphyromonas endodontalis (P.endodontalis) on expression of monocyte chemotactic protein-1 (MCP-1) mRNA and protein in MC3T3-E1 cells and the role of p38 mitogen-activated　protein　kinase (MAPK) and nuclear factor-kB(NF-kB）in the process. METHODS: MC3T3-E1 cells were treated with different concentrations of P.endodontalis LPS(0-50mg/L) and 20 mg/L P.endodontalis LPS for different hours (0-48 h). The expression of MCP-1 mRNA was detected by real-time reverse transcription PCR(RT-PCR) and protein was detected by enzyme-1inked immunosorbent assay (ELISA). MC3T3-E1 cells were pretreated with SB203580 (inhibitor of p38MAPK) and BAY11-7082 (inhibitor of NF-kB) for 1h, and then were treated with 20 mg/L P.endodontalis LPS for 24 h, the expression of MCP-1 mRNA was also detected by RT-PCR. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. RESULTS: The level of MCP-1 mRNA and protein increased significantly after treatment with different concentrations of P.endodontalis LPS (0-50 mg/L), which indicated that P.endodontalis LPS induced osteoblasts to express MCP-1 in a dose dependent manners. During the observation time (0-48 h), the impact of 20 mg/L P.endodontalis LPS on induction of MCP-1 in MC3T3-E1 cells exhibited a time-dependent manner. The expression of MCP-1 mRNA decreased significantly after pretreated with 10 mol/L SB203580 and BAY11-7082 for 1 h,and the inhibitory effect of SB203580 was stronger than BAY11-7082. CONCLUSIONS: P.endodontalis LPS may induce the expression of MCP-1 mRNA and protein in MC3T3-E1 cells through the signaling pathway of p38MAPK and NF-kB.

[Effects of lipopolysaccharides from Porphyromonas endodontalis on the expression of MIP-1α in mouse osteoblasts].

PURPOSE: To investigate the effects of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of macrophageinflammatoryprotein-1α (MIP-1α) mRNA and protein levels in MC3T3-E1 cells and the influence of curcumin in the process. METHODS: MC3T3-E1 cells were treated with 20 mg/L P.e-LPS for different times (0-48 h). The expression of MIP-1α mRNA and protein was detected by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) and enzyme linked immunosorbent assay(ELISA). MC3T3-E1 cells were pretreated with inhibitor of (curcumin) for 1 h, and then treated with 20 mg/L P.e-LPS. The expression of MIP-1α was also detected by real-time RT-PCR and ELISA.Statistical analysis was performed using one-way ANOVA and Dunnett's t test with SPSS 13.0 software package. RESULTS: In the observation time (0-48 h), the impact of 20 P.e-LPS mg/L on induction of MIP-1α in MC3T3-El cells exhibited a time-dependent manner. The expression of MIP-1α mRNA and protein decreased significantly after pretreatment with 10 µmol/L curcumin for 1 h. CONCLUSIONS: The results suggest that P.e-LPS may mediate MIP-1α expression in MC3T3-E1 cells, and curcumin has a significant inhibitory effect on this process.

Sirtuin 1 regulates matrix metalloproteinase-13 expression induced by Porphyromonas endodontalis lipopolysaccharide via targeting nuclear factor-κB in osteoblasts.

Porphyromonas endodontalis lipopolysaccharide (P.e LPS) is an important initiating factor for periapical inflammation and bone destruction. Matrix metalloproteinase-13 (MMP-13) has been shown to participate in the formation and diffusion of periapical bone lesion in chronic apical periodontitis. Sirtuin 1 (SIRT1) is a key regulator of inflammation in mammalian cells which suppresses the release of inflammatory mediators. This study aimed to explore the role of SIRT1 in regulating MMP-13 expression induced by P.e LPS in osteoblasts. P.e LPS stimulated MMP-13 expression in MC3T3-E1 cells. Knockdown of SIRT1 reinforced the increase of MMP-13mRNA expression induced by P.e LPS. SIRT1 activator resveratrol significantly reduced the expression of MMP-13 and SIRT1 inhibitor EX-527 enhanced the expression of MMP-13. Moreover, SIRT1 activation with resveratrol inhibited acetylation of NF-κB p65 and NF-κB transcriptional activity, which were enhanced by P.e LPS. In addition, NF-κB p65 was involved in P.e LPS-induced MMP-13 expression via directly binding to the MMP-13 promoter. However, SIRT1 activation significantly interfered with this binding. These findings strongly suggest that P.e LPS induces MMP-13 expression in osteoblasts, and SIRT1 suppresses this expression of MMP-13 through targeting NF-κB p65. This provides new insights into understanding the actions of SIRT1 on anti-inflammatory and anti-bone resorption activity.

[Inhibiting effect of transforming growth factor ß3 on IL-6 expression in MG63 induced by lipopolysaccharide].

PURPOSE: To explore the effect of transforming growth factor ß3 (TGF-ß3) on IL-6 expression in inflammatory MG63, and the mechanism by which TGF-ß3 exert its anti-inflammatory effect. METHODS: Cell line MG63 was stimulated by 20 µg/mL lipopolysaccharide of Porphyromonas endodontalis (P.e-LPS) to establish the inflammatory model of osteoblast. TGF-ß3 or TGFß1 varying from 5 to 20 ng/mL was added together with P.e-LPS for 24 h, then the mRNA expression of IL-6 was detected by real-time PCR, the role of TGF-ß3 on IL-6 protein was further verified by ELISA. MG63 was pretreated with 10 ng/mL TGF-ß3 for 30 min in RPMI 1640 medium without fetal bovine serum (FBS), then the cells were cultured for another 20 min with 20 µg/mL P.e-LPS, the phosphorylation level of ERK1/2 was measured by Western blot. Statistical analysis was performed using one-way ANOVA with SPSS13.0 software package. RESULTS: The results of real-time PCR revealed that, when MG63 was treated with 20 µg/mL P.e-LPS alone, the mRNA expression of IL-6 increased significantly(P<0.01). When TGF-ß1 was added with P.e-LPS, it could barely decrease IL-6 prominently at the highest concentration (P<0.05).Whereas, the inhibition effect of TGF-ß3 on IL-6 was dramatic (P<0.01), ELISA results showed that 10-20 ng/mL TGF-ß3 blocked the IL-6 expression at protein level (P<0.05). 20 µg/mL P.e-LPS promoted the phosphorylation level of ERK1/2 in MG63(P<0.01), while with 10 ng/mL TGF-ß3, the effect of P.e-LPS on ERK1/2 was blocked(P<0.05). CONCLUSIONS: TGF-ß3 is more potent than TGF-ß1 in inhibiting MG63, and ERK1/2 is involved in its anti-inflammatory effect.

[Effect of lipopolysaccharides from Porphyromonas endodontalis on the expression of interleukin-34 in mouse osteoblasts].

PURPOSE: To investigate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (P.e) on the expression of interleukin-34 (IL-34) mRNA in MC3T3-E1 cells and the role of p38MAPK, ERK1/2, NF-κB and SIRT1 in the process. METHODS: MC3T3-E1 cells were treated with different concentrations of P.e-LPS(0-50 mg/L) and 20 mg/L P.e-LPS for different time (0-24 h). The expression of IL-34 mRNA was detected by real-time reverse transcription-polymerase chain reaction (real time RT-PCR). MC3T3-E1 cells were pretreated with inhibitor of NF-κB(BAY 11-7082),inhibitor of p38MAPK (SB203580), inhibitor of ERK1/2 (PD98059), agonist of sirtuin1 (SIRT1) [resveratrol (RES)] and inhibitor of SIRT1 (EX-527) for 1 h, and then were treated with 20 mg/L P.e-LPS. The expression of IL-34 mRNA was detected by real time RT-PCR. Statistical analysis was performed using one-way ANOVA and Dunnett t test with SPSS 13.0 software package. RESULTS: The level of IL-34 mRNA increased significantly after treatment with different concentrations of P.e-LPS(0-50 mg/L)，which indicated that P.e-LPS induced osteoblasts to express IL-34 mRNA in a dose-dependent manner. Maximal induction of IL-34 mRNA expression was observed in MC3T3-E1 cells treated with 20 mg/L P.e-LPS for 24 h.At 48 h, the expression of IL-34 mRNA decreased gradually. The mRNA of IL-34 decreased significantly after pretreatment with 10 µmol/L BAY-117082, SB203580 and PD98059 for 1 h. P.e-LPS-induced IL-34 upregulation was attenuated by pretreatment with RES, but increased by EX-527. CONCLUSIONS: These results suggest that P.e-LPS may mediate IL-34 mRNA expression in MC3T3-E1 cells. This process is dependent, at least in part, on p38MAPK, ERK1/2, NF-κB and SIRT1 signaling pathways.