SIRT7 inhibits the aging and inflammatory damage of hPDLFs by suppressing the AKT/mTOR.

Periodontitis seriously affects oral health worldwide. Despite extensive efforts in prevention and treatment methods over the years, the prevalence of periodontitis in the population has not decreased. DNA damage-induced cellular senescence may be one of the mechanisms underlying periodontitis.Sirtuin7 (SIRT7) has deacetylase activity and regulates a variety of biological processes, including cell proliferation, death, and DNA damage repair.Increasing evidence confirms the crucial role of SIRT7 in age-related and inflammatory diseases. However, the mechanism of action of SIRT7 in periodontitis remains unclear. Our study demonstrates that SIRT7 is downregulated in human periodontal ligament fibroblasts induced by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS). Overexpression of the SIRT7 gene significantly reduces the production of senescence-related molecules P53, P21, P16, as well as inflammatory cytokines IL-1ß and TNF-α stimulated by Pg-LPS. Furthermore, overexpression of the SIRT7 gene significantly decreases the phosphorylation levels of AKT and mTOR in Pg-LPS-treated hPDLFs. Conversely, SIRT7 gene knockdown exhibits opposite effects compared to overexpression in Pg-LPS-treated hPDLFs. In conclusion, our findings indicate that SIRT7 can inhibit Pg-LPS-induced senescence and consequently suppress the secretion of inflammatory cytokines through the AKT/mTOR pathway. As a result, SIRT7 could be regarded a viable pharmaceutical target for clinical periodontitis treatment.

Synergistic effects of enamel matrix derivatives and surface morphology of anodized titanium on osteogenic differentiation of bone marrow mesenchymal stem cells sheet.

OBJECTIVE: To explore the potential osteogenic induction mechanism of enamel matrix derivatives (EMDs) on bone marrow mesenchymal stem cell (BMSC) sheets with different titanium surface morphologies. METHODS: The BMSCs were inoculated on the surfaces of titanium alloys with different morphologies: anodic oxidation (AO), sand-blasted, large grit and acid-etched, and no treatment (control). The proliferation and osteogenic differentiation of BMSCs on the different surface morphologies were observed with the same concentration of EMDs. To further understand the osteogenic mechanism of EMDs on BMSC sheets with different morphologies, a real-time RT-PCR and a western blot were used to detect the overall levels of osteogenic genes and osteogenic proteins. Finally, to verify the osteogenic effect of BMSC sheets stimulated by EMDs in vivo, BMSC sheets with different morphologies were implanted into the subcutaneous tissue of the back of nude mice, and the bone formation was detected by HE staining. RESULTS: The EMDs and surface morphology in the AO group synergically increased the expression levels of osteogenic active factors (RUNX2, OSX and OCN) and enhanced the osteogenic differentiation effect of BMSCs. The in vivo experiments showed that the BMSC sheets in the AO group were rich in osteogenic active factors, and promoted the formation of ectopic bone tissue after implantation into the subcutaneous tissue of the back of nude mice. CONCLUSION: EMDs and AO morphology synergically enhance the secretion of bone osteogenic active factors of BMSCs and promote the formation of heterotopic bone.

miR-153-3p inhibits osteogenic differentiation of BMSCs by down-regulating the expression of RUNX2 in a high glucose environment.

To study the effect of miR-153-3p on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in a high glucose environment and its potential mechanism. The results showed that high glucose inhibited the osteogenic differentiation of BMSCs, and the expression of miR-153-3p increased during osteogenic differentiation. Further experiments found that in BMSCs induced by high glucose, overexpression of miR-153-3p inhibited the osteogenic differentiation of BMSCs, and the expressions of osteogenesis-related genes bone sialoprotein, Collagen I and alkaline phosphatase were down-regulated, while silencing of miR-153-3p alleviated the inhibition effect. The dual-luciferase reporter gene assay confirmed that the 3'-untranslated region (3'-UTR) of runt related transcription factor 2 (RUNX2) had a targeted binding site with miR-153-3p and a negative regulatory effect. Molecular studies further confirmed that miR-153-3p inhibited the osteogenic differentiation of BMSCs by targeting the 3'-UTR of RUNX2. In conclusion, our study found that as one key regulator of high glucose affecting the osteogenic differentiation of BMSCs, miR-153-3p may play a negative regulatory role by inhibiting the expression of RUNX2.

Enamel matrix derivative expedites osteogenic differentiation of BMSCs via Wnt/ß-catenin pathway in high glucose microenvironment.

INTRODUCTION: The influence of enamel matrix derivative (EMD) on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was explored in high glucose (HG) microenvironment with interaction of Wnt/ß-catenin pathway. MATERIALS AND METHODS: Extraction of BMSCs from Sprague-Dawley rats, culture, and identification were manifested. The cells were treated with different concentration of EMD in HG to figure out the most available concentration for proliferation and osteogenic differentiation. Then, observation of cell growth curve and cell cycle changes, and detection of Osterix, runt-related transcription factor 2 (Runx2), COL-I, early osteogenic indexes, Calcium salt deposition, and ß-catenin protein in Wnt/ß-catenin pathway were assured. After adding Wnt/ß-catenin pathway inhibitor (XAV-939) in the cells with osteogenesis induction, detection of binding of ß-catenin to Osterix was clarified. RESULTS: Via identification BMSCs cultured in vitro was qualified. Different concentrations of EMD could accelerate cell proliferation in HG and osteogenesis induction, and 75 µg/mL EMD had the best effect. The HG augmented BMSCs proliferation and the propidium iodide index of flow cytometry cycle was elevated in HG, which were strengthened via the EMD. After BMSCs' osteogenesis induction, Osterix, Runx2, CoL-1, early osteogenic indexes, and calcium salt deposition were reduced, but elevated via EMD. ß-Catenin was the lowest in the HG, but elevated after EMD. After addition of XAV-939, reduction of ß-catenin and the downstream (Osterix and Runx2) were manifested. Detection of binding protein bands was in ß-catenin and Osterix of the HG after EMD treatment. CONCLUSION: EMD may facilitate the osteogenic differentiation of BMSCs via activating the Wnt/ß-catenin pathway in HG.

Enamel matrix derivative (EMD) enhances the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

To investigate the EMD's capacity in BMSCs osteogenic differentiation. In vivo and in vitro, BMSCs were treated with EMD, scanning electron microscopy, and Alizarin Red staining were used to detect the changes in the osteogenic ability of BMSCs, and the proliferation ability of BMSCs was evaluated by CCK8. In addition, by adding xav939, a typical inhibitor of Wnt/ß-catenin signaling pathway, the regulatory function of Wnt/ß-catenin signaling was clarified. The results showed that EMD promote cell proliferation and 25 µg/ml EMD had the most significant effect. Cells inducing osteogenesis for 2 and 3 even 4 weeks, the cell staining is deeper in EMD treated group than that of the control (P < 0.05) by alizarin Red staining, suggesting more mineralization of BMSCs. In vivo implanting the titanium plate wrapped with 25 µg/ml EMD treated-BMSC film into nude mice for 8 weeks, more nodules were formed on the surface of the titanium plate than that the control (P < 0.05). HE showed that there is a little blue-violet immature bone-like tissue block. Besides, the expression of RUNX Family Transcription Factor 2 (Runx2), Osterix, Osteocalcin (OCN), collagen I (COLI), alkaline phosphatase (ALP) and ß-catenin were inhibited in xav939 group (P < 0.05); Inversely, all were activated in EMD group (P < 0.05). In conclusion, EMD promoted the proliferation and osteogenic differentiation of BMSCs. EMD's function on BMSCs might be associated with the Wnt/ß-catenin signaling pathway.