Resveratrol Alleviates Osteoporosis by Promoting Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells via SITR1/PI3K/AKT Pathway / El Resveratrol Alivia la Osteoporosis al Promover la Diferenciación Osteogénica de las Células Madre Mesenquimales de la Médula Ósea a Través de la Vía SITR1/PI3K/AKT

SUMMARY: Senile osteoporosis is mainly caused by reduced osteoblast differentiation and has become the leading cause of fractures in the elderly worldwide. Natural organics are emerging as a potential option for the prevention and treatment of osteoporosis. This study was designed to study the effect of resveratrol on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in osteoporosis mice. A mouse model of osteoporosis was established by subcutaneous injection of dexamethasone and treated with resveratrol administered by gavage. In vivo and in vitro, we used western blot to detect protein expression, and evaluated osteogenic differentiation of BMSCs by detecting the expression of osteogenic differentiation related proteins, calcium deposition, ALP activity and osteocalcin content. Resveratrol treatment significantly increased the body weight of mice, the level of serum Ca2+, 25(OH)D and osteocalcin, ration of bone weight, bone volume/total volume, trabecular thickness, trabecular number, trabecular spacing and cortical thickness in osteoporosis mice. In BMSCs of osteoporosis mice, resveratrol treatment significantly increased the expression of Runx2, osterix (OSX) and osteocalcin (OCN) protein, the level of calcium deposition, ALP activity and osteocalcin content. In addition, resveratrol treatment also significantly increased the expression of SIRT1, p-PI3K / PI3K and p-AKT / AKT in BMSCs of osteoporosis mice. In vitro, resveratrol increased the expression of SIRT1, p-PI3K / PI3K and p-AKT / AKT, Runx2, OSX and OCN protein, the level of calcium deposition, ALP activity and osteocalcin content in BMSCs in a concentration-dependent manner, while SIRT1 knockdown significantly reversed the effect of resveratrol. Resveratrol can attenuate osteoporosis by promoting osteogenic differentiation of bone marrow mesenchymal stem cells, and the mechanism may be related to the regulation of SIRT1/PI3K/AKT pathway.

La osteoporosis senil es causada principalmente por una diferenciación reducida de osteoblastos y se ha convertido en la principal causa de fracturas en las personas mayores en todo el mundo. Los productos orgánicos naturales están surgiendo como una opción potencial para la prevención y el tratamiento de la osteoporosis. Este estudio fue diseñado para estudiar el efecto del resveratrol en la diferenciación osteogénica de las células madre mesenquimales de la médula ósea (BMSC) en ratones con osteoporosis. Se estableció un modelo de osteoporosis en ratones mediante inyección subcutánea de dexametasona y se trató con resveratrol administrado por sonda. In vivo e in vitro, utilizamos Western blot para detectar la expresión de proteínas y evaluamos la diferenciación osteogénica de BMSC detectando la expresión de proteínas relacionadas con la diferenciación osteogénica, la deposición de calcio, la actividad de ALP y el contenido de osteocalcina. El tratamiento con resveratrol aumentó significativamente el peso corporal de los ratones, el nivel sérico de Ca2+, 25(OH)D y osteocalcina, la proporción de peso óseo, el volumen óseo/ volumen total, el espesor trabecular, el número trabecular, el espaciado trabecular y el espesor cortical en ratones con osteoporosis. En BMSC de ratones con osteoporosis, el tratamiento con resveratrol aumentó significativamente la expresión de las proteínas Runx2, osterix (OSX) y osteocalcina (OCN), el nivel de deposición de calcio, la actividad de ALP y el contenido de osteocalcina. Además, el tratamiento con resveratrol también aumentó significativamente la expresión de SIRT1, p-PI3K/PI3K y p-AKT/AKT en BMSC de ratones con osteoporosis. In vitro, el resveratrol aumentó la expresión de las proteínas SIRT1, p-PI3K/PI3K y p- AKT/AKT, Runx2, OSX y OCN, el nivel de deposición de calcio, la actividad de ALP y el contenido de osteocalcina en BMSC de manera dependiente de la concentración, mientras que La caída de SIRT1 revirtió significativamente el efecto del resveratrol. El resveratrol puede atenuar la osteoporosis al promover la diferenciación osteogénica de las células madre mesenquimales de la médula ósea, y el mecanismo puede estar relacionado con la regulación de la vía SIRT1/PI3K/AKT.

Assessment of the osteogenic effect after maxillary sinus floor elevation and simultaneous implantation with or without bone grafts by analyzing trabecular bone parameters: a retrospective study

Abstract Objective: The aim of this population-based retrospective study was to compare the osteogenic effect of newly formed bone after maxillary sinus floor elevation (MSFE) and simultaneous implantation with or without bone grafts by quantitatively analyzing trabecular bone parameters. Methodology: A total of 100 patients with missing posterior maxillary teeth who required MSFE and implantation were included in this study. Patients were divided into two groups: the non-graft group (n=50) and the graft group (n=50). Radiographic parameters were measured using cone beam computed tomography (CBCT), and the quality of newly formed bone was analyzed by assessing trabecular bone parameters using CTAn (CTAnalyzer, SkyScan, Antwerp, Belgium) software. Results: In the selected regions of interest, the non-graft group showed greater bone volume/total volume (BV/TV), bone surface/total volume (BS/TV), trabecular number (Tb. N), and trabecular thickness (Tb. Th) than the graft group (p<0.001). The non-graft group showed lower trabecular separation (Tb. Sp) than the graft group (p<0.001). The incidence of perforation and bleeding was higher in the graft group than in the non-graft group (p<0.001), but infection did not significantly differ between groups (p>0.05). Compared to the graft group, the non-graft group showed lower postoperative bone height, gained bone height and apical bone height (p<0.001). Conclusion: MSFE with and without bone grafts can significantly improve bone formation. In MSFE, the use of bone grafts hinders the formation of good quality bone, whereas the absence of bone grafts can generate good bone quality and limited bone mass.

Effect of low concentration of sodium fluoride on osteogenic/odontogenic differentiation of human dental pulp cells / 口腔疾病防治

Objective@#To study the effect of low concentrations of sodium fluoride on the osteogenic/odontogenic differentiation of human dental pulp cells (hDPCs) in vitro.@*Methods@#This study was reviewed and approved by the Ethics Committee. hDPCs were cultured using a modified tissue explant technique in vitro. The effects of different concentrations of sodium fluoride on the proliferation of hDPCs were measured by methylthiazol tetrazolium (MTT) assay. Appropriate concentrations were added to the osteogenic/odontogenic differentiation induction medium, and the cells were induced in vitro. Alizarin red S staining was used to detect the osteoblastic/odontogenic differentiation ability of the cells, and the mRNA expression of the key differentiation factors was detected by RT-qPCR. Moreover, the expression of key molecules of endoplasmic reticulum stress (ERS) was detected by RT-qPCR and Western blot. The data were analyzed with the SPSS 18.0 software package.@*Results@#Low concentration of NaF (0.1 mmol/L) could stimulate cell proliferation in vitro, while a high concentration (5-10 mmol/L) could inhibit cell proliferation (P<0.05). According to the literature and the experimental data, 0.1 mmol/L NaF was selected as the following experimental concentration. The levels of alizarin red S staining were increased after NaF induction of mixed osteogenic/odontogenic differentiation in vitro. The mRNA expression levels of key molecules for osteogenic/odontogenic differentiation, dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP) and osteocalcin (OCN), were increased (P<0.05). The mRNA levels of ERS markers (splicing x-box binding protein-1 (sXBP1), glucose-regulated protein 78 (GRP78) and activating transcription Factor 4 (ATF4) were increased in NaF-treated cells. The protein expression levels of key ER stress molecules (phosphorylated RNA-activated protein kinase-like ER-resident kinase (p-PERK), phosphorylated eukaryotic initiation factor-2α (p-eIF2α) and ATF4) were higher in NaF-treated cells.@*Conclusion@#A low concentration of NaF promotes the osteogenic/odontogenic differentiation of hDPCs and increases the level of ER stress.

LED red light up-regulates MAPK signal to promote osteogenic/odontogenic differentiation of human dental pulp stem cells in an inflammatory environment / 口腔疾病防治

Objective @#To study the effect of light-emitting diode (LED) red light on the osteogenic/odontogenic differentiation of human dental pulp stem cells (hDPSCs) and its mechanism were discussed. @*Methods@#This study has been reviewed and approved by the Ethics Committee. hDPSCs were cultured by tissue block enzyme digestion. The proliferative capacity of hDPSCs was detected by the CCK-8 at days 1, 3, 5 and 7 under stimulation with 0, 1, 5 and 10 μg/mL lipopolysaccharide (LPS), and the LPS stimulatory concentration was screened. The CG group (mineralization induction), LPS+CG group, and LPS+CG+ (2, 4, 6, 8, and 10 J/cm2) LED red light groups were set. On day 7, alkaline phosphatase (ALP) staining and ALP activity were determined. Relative expression levels of the ALP, osterix (OSX), dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotein (DSPP) genes were measured by qRT-PCR. On day 21, alizarin red staining and calcium nodule quantitative determination were performed to screen the best light energy. The LPS+CG group and LPS+CG+LED group (optimal energy) were set up, and the secretion and expression levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected by ELISAs on days 1, 3, 5 and 7. The relative expression levels of the extracellular regulated protein kinases 1/2 (ERK1/2), p38, c-Jun N-terminal kinase (JNK), and extracellular regulated protein kinases 5 (ERK5) proteins and their phosphorylated proteins in the MAPK signaling pathway were detected by Western blots. After the pathway was blocked, the relative expression levels of the ALP, OSX, DMP-1, and DSPP proteins after LED red light irradiation on day 7 were detected by Western blots.@*Results@# CCK-8 assays showed that the proliferation of hDPSCs induced by 10 μg/mL LPS was lower than that of the 0, 1, and 5 μg/mL groups on the 5th and 7th days (P<0.05), and 10 μg/mL was selected as the LPS stimulatory concentration in the follow-up experiment. ALP staining, ALP activity, gene expression levels of ALP, OSX, DMP-1 and DSPP and calcium nodule quantification in the LPS+CG+4 J/cm2 group were higher than those in the other treatment groups (P<0.05). 4 J/cm2 LED red light had the strongest ability to promote osteogenic/odontogenic differentiation and was used as the LED light energy density in subsequent experiments. ELISA showed that the secretion and expression levels of TNF-α and IL-1β in the LPS+CG+LED group were lower than those in the LPS+CG group on the 5th and 7th days (P<0.05). Western blot analysis showed that 4 J/cm2 LED red light promoted the expression levels of the p-ERK1/2, p-p38, p-JNK and p-ERK5 proteins. After the MAPK pathway was blocked, the expression levels of the ALP, OSX, DMP-1, and DSPP proteins in the LPS+CG+LED+U0126 (ERK1/2 inhibitor), SP600125 (JNK inhibitor), and BIX02189 (ERK5 inhibitor) groups were lower than those in the LPS+CG+LED group (P<0.001). The protein expression levels of ALP, OSX and DMP-1 in the LPS+CG+LED+SB203580 (p38 inhibitor) group were not significantly different from those in the LPS+CG+LED group (P>0.05).@*Conclusion@#In inflammatory conditions, LED red light promotes osteogenic/odontogenic differentiation of hDPSCs. This effect may be attributed to enhancement of the ERK1/2, JNK, and ERK5 signaling pathways, which reduces the production of the inflammatory cytokines TNF-α and IL-1β.

Regulation of osteogenic differentiation under hypoxia by EphrinB2/EphB4 in MC3T3-E1 cells / 口腔疾病防治

Objective @# To investigate the effect of erythropoietin producing hepatocyte kinase receptor ligand B2-erythropoietin producing hepatocyte kinase receptor B4 (EphrinB2/EphB4) on the osteogenic differentiation of MC3T3-E1 cells in a hypoxic environment to provide experimental evidence for hypoxia regulation of osteoblast differentiation.@*Methods @# Control groups and cobalt chloride (CoCl2)-induced hypoxia groups were set up first. qRT-PCR was used to detect the mRNA expression of the osteogenic markers alkaline phosphatase (ALP), collogen1 (COL I), runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN). ALP staining was used to detect the activity of cell alkaline phosphatase after osteogenic induction. The mRNA and protein expression levels of hypoxia inducible factor-1α (HIF-1α), EphrinB2 and EphB4 in the two groups were detected via qRT-PCR and Western blot. Then, the CoCl2 + inhibitor group was established. NVP-BHG712, an EphB4 phosphorylation inhibitor, was added to this group to prevent EphrinB2 from binding to EphB4 and producing signals. qRT-PCR and Western blot were used to detect the mRNA and protein expression of osteogenic markers, including ALP, RUNX2, COL I, and OCN. ALP staining and Alizarin red S staining were used to measure osteoblast differentiation and mineralization. @*Results @# Compared with the control group, the mRNA expression of the osteogenic differentiation markers ALP, RUNX2, COL-1, and OCN in MC3T3-E1 cells increased, and ALP activity and mineralization were enhanced under CoCl2-induced hypoxia in vitro (P<0.05). Additionally, the expression of HIF-1α, EphrinB2 and EphB4 was upregulated at the mRNA and protein levels under hypoxia (P<0.05). When NVP-BHG712 was used to block the connection between EphrinB2 and EphB4, the expression of osteogenic markers and ALP activity and mineralization were decreased (P<0.05).@*Conclusion@#EphrinB2/EphB4 can promote osteogenic differentiation of MC3T3-E1 cells and increase the expression of osteogenic markers and tissue mineralization in a hypoxic environment.

Study on the role and mechanism of osteogenesis induced by advanced platelet-rich fibrin and β-tricalcium phosphate complex / 口腔疾病防治

Objective @#To investigate the role and mechanism of bone formation caused by the ratio of advanced platelet-rich fibrin (A-PRF) and β-tricalcium phosphate (β-TCP) in rabbit femur defect model, which provides a new idea for clinical treatment of bone defect.@*Methods @#Twenty-four New Zealand white rabbits were divided into model group, 1∶1 complex group (A-PRF∶β-TCP=1∶1), 2∶1 complex group (A-PRF∶β- TCP=2∶1) and 4∶1 complex group (A-PRF∶β- TCP=4∶1）, with 6 rabbits in each group. Femoral defect models were constructed in each group. In the composite group, the bone defect was filled with composite material, while in the model group, no material was filled. After 8 weeks, the animals were euthanized and specimens were collected. Bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.SP) and trabecular number (Tb.N) in femoral defect tissue were measured by micro-CT and photographed. Hematoxylin - eosin staining was used to detect the pathological changes of new bone tissue. The morphological changes of the new bone tissue were observed by scanning electron microscopy. Determination of phospho-mitogen activated protein kinase p38 (p-p38MAPK), CCAAT/enhancer binding protein homologous protein (CHOP) and phospho-cysteine aspartic protease-3 (p-Caspase3) in newborn femur by ELISA. The mRNA expressions of osteoprotegerin (OPG), bone morphogenetic protein-2 (BMP-2), receptor activator of nuclear factor kappa-B ligand (RANKL) and p38MAPK were detected by real-time quantitative PCR. The expression of OPG, BMP-2, RANKL, p-p38MAPK and p-Caspase3 protein in the new bone tissue was observed by immunohistochemistry. @*Results @#In the model group, bone formation in the femoral defect area was slow and osteogenic quality was poor. Compared with the model group, the bone formation and neocapillaries of femoral defect area in the complex group was good, BMD, BV.TV, Tb.Th, Tb.N were increased, and Tb.Sp were decreased, the expressions of p-p38MAPK, CHOP and p-Caspase3 were decreased, and the mRNA and protein expressions of OPG and BMP-2 were increased. The mRNA expression of RANKL and p38MAPK was decreased. Apoptosis in new bone tissue of each group showed the lowest apoptosis rate in samples of the 2∶1 complex group (P<0.05); A-PRF: β-TCP=2∶1 ratio has the best osteogenic effect. @*Conclusion@#The complex composed of A-PRF and β-TCP can promote the expression of OPG, inhibit the expression of RANKL and phosphorylation of p38MAPK, reduce the apoptosis of new bone tissue cells, and promote osteogenic differentiation.

Study on the effects and mechanism of luteolin on osteogenic repair of bone defects / 中国药房

OBJECTIVE To investigate the effects and mechanism of luteolin on osteogenic repair of bone defects. METHODS The targets and potential pathways of luteolin in the treatment of bone defects were screened by network pharmacology method， and then the top 2 targets were selected by Hub gene screening for molecular docking verification， with binding energy as the evaluation standard. In vitro experiments were conducted on rat bone mesenchymal stem cells （BMSC） and rat umbilical vein endothelial cells （RUVEC）. Phenotypic validation was performed using alkaline phosphatase staining， alizarin red S staining， and in vitro angiogenesis experiments. Western blot assay was used to detect the protein expressions of phosphatidylinositol 3 kinase （PI3K） and protein kinase 1 （Akt1）， so as to validate the mechanism of luteolin on osteogenic differentiation of BMSC and angiogenesis of RUVEC in vitro. RESULTS The results of network pharmacology showed that the effects of luteolin on vascular formation and bone repair in bone defects were mainly related to Akt1， SRC， estrogen receptor 1， epidermal growth factor receptor， cyclooxygenase 2， matrix metalloproteinase 9 targets， and were closely related to PI3K-Akt signaling pathway. The results of molecular docking showed that luteolin binding to Akt1 and SRC proteins was stable. The results of in vitro experiments showed that luteolin could significantly improve the expressions and activities of alkaline phosphatase in BMSC， increased the number of calcium salt deposits and calcified nodules， and promoted calcification of BMSC. Compared with luteolin 0 μmol/L group， the angiogenesis ability of RUVEC was enhanced significantly in luteolin 1， 10 μmol/L groups， the length of blood vessels and the protein expressions of PI3K and Akt1 were significantly increased （P＜0.05 or P＜0.01）； the higherthe concentration， the better the effect. CONCLUSIONS Luteolin may play a role in promoting angiogenesis and bone repair at the fracture site by activating PI3K/Akt signaling pathway and promoting the protein expressions of PI3K and Akt1.

Overview of the main biological mechanisms linked to changes in periodontal ligament stem cells and the inflammatory microenvironment / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Periodontitis is a complex chronic inflammatory disease. The invasion of pathogens induces the inflammatory microenvironment in periodontitis. Cell behavior changes in response to changes in the microenvironment, which in turn alters the local inflammatory microenvironment of the periodontium through factors secreted by cells. It has been confirmed that periodontal ligament stem cells (PDLSCs) are vital in the development of periodontal disease. Moreover, PDLSCs are the most effective cell type to be used for periodontium regeneration. This review focuses on changes in PDLSCs, their basic biological behavior, osteogenic differentiation, and drug effects caused by the inflammatory microenvironment, to provide a better understanding of the influence of these factors on periodontal tissue homeostasis. In addition, we discuss the underlying mechanism in detail behind the reciprocal responses of PDLSCs that affect the microenvironment.

Mechanism of the Notch1 signaling pathway regulating osteogenic factor influences lumbar disc calcification / 中国骨伤

OBJECTIVE@#To explore the mechanism of the Notch1 signaling pathway in regulating osteogenic factors and influencing lumbar disc calcification.@*METHODS@#Primary annulus fibroblasts from SD rats were isolated and subcultured in vitro. The calcification-inducing factors bone morphogenetic protein-2 (BMP-2) and basic fibroblast growth factor (b-FGF) were added to separate groups to induce calcification, which were referred to as the BMP-2 group and the b-FGF group, respectively. A control group was also set up, which was cultured in normal medium. Subsequently, cell morphology and fluorescence identification, alizarin red staining, ELISA, and quantitative real-time polymerase chain reaction (QRT-PCR) were performed to determine the effect of calcification induction. Cell grouping was performed again, including the control group, the calcification group (adding the inducer BMP-2), the calcification + LPS group(adding the inducer BMP-2 and the Notch1 pathway activator LPS), and the calcification + DAPT group (adding the inducer BMP-2 and the Notch1 pathway inhibitor DAPT). Alizarin red staining and flow cytometry were used to detect cell apoptosis, ELISA was used to detect the content of osteogenic factors, and Western blot was used to detect the expression of BMP-2, b-FGF, and Notch1 proteins.@*RESULTS@#The induction factor screening results showed that the number of mineralized nodules in fibroannulus cells in BMP-2 group and b-FGF group was significantly increased, and the increase was greater in the BMP-2 group Meanwhile, ELISA and Western blot results showed that BMP-2, b-FGF and mRNA expression levels of BMP-2, b-FGF and Notch1 in the induced group were significantly increased (P<0.01). The results of the mechanism of Notch1 signaling pathway affecting lumbar disc calcification showed that compared to calcified group, the number of fibroannulus cell mineralization nodules, apoptosis rate, BMP-2, b-FGF content, the expression levels of BMP-2, b-FGF, and Notch1 proteins were further increased significantly However, the number of mineralization nodules, apoptosis rate, BMP-2 and b-FGF levels, BMP-2, b-FGF and Notch1 protein expression levels were decreased in the calcified +DAPT group (P<0.05 or P<0.01).@*CONCLUSION@#Notch1 signaling pathway promotes lumbar disc calcification through positive regulation of osteogenic factors.

Mechanism of miR-26a-5p/cAMP response element binding protein 1 molecular axis regulating osteogenic differentiation of adipose-derived mesenchymal stem cells / 中国修复重建外科杂志

OBJECTIVE@#To investigate the regulatory effects of miR-26a-5p on the osteogenic differentiation of adipose-derived mesenchymal stem cells (ADSCs) by regulating cAMP response element binding protein 1 (CREB1).@*METHODS@#The adipose tissues of four 3-4 weeks old female C57BL/6 mice were collected and the cells were isolated and cultured by digestion separation method. After morphological observation and identification by flow cytometry, the 3rd-generation cells were subjected to osteogenic differentiation induction. At 0, 3, 7, and 14 days after osteogenic differentiation induction, the calcium deposition was observed by alizarin red staining, ALP activity was detected, miR- 26a-5p and CREB1 mRNA expressions were examined by real-time fluorescence quantitative PCR, and CREB1 protein and its phosphorylation (phospho-CREB1, p-CREB1) level were measured by Western blot. After the binding sites between miR-26a-5p and CREB1 was predicted by the starBase database, HEK-293T cells were used to conduct a dual-luciferase reporter gene experiment to verify the targeting relationship (represented as luciferase activity after 48 hours of culture). Finally, miR-26a-p inhibitor (experimental group) and the corresponding negative control (control group) were transfected into ADSCs. Alizarin red staining, ALP activity, real-time fluorescent quantitative PCR (miR-26a-5p) and Western blot [CREB1, p-CREB1, Runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN)] were performed at 7 and 14 days after osteogenic induction culture.@*RESULTS@#The cultured cells were identified as ADSCs. With the prolongation of osteogenic induction culture, the number of calcified nodules and ALP activity significantly increased ( P<0.05). The relative expression of miR-26a-5p in the cells gradually decreased, while the relative expressions of CREB1 mRNA and protein, as well as the relative expression of p-CREB1 protein were increased. The differences were significant between 7, 14 days and 0 day ( P<0.05). There was no significant difference in p-CREB1/CREB1 between different time points ( P>0.05). The starBase database predicted that miR-26a-5p and CREB1 had targeted binding sequences, and the dual-luciferase reporter gene experiment revealed that overexpression of miR-26a-5p significantly suppressed CREB1 wild-type luciferase activity ( P<0.05). After 7 and 14 days of osteogenic induction, compared with the control group, the number of calcified nodules, ALP activity, and relative expressions of CREB1, p-CREB1, OCN, and RUNX2 proteins in the experimental group significantly increased ( P<0.05). There was no significant difference in p-CREB1/CREB1 between the two groups ( P>0.05).@*CONCLUSION@#Knocking down miR-26a-5p promoted the osteogenic differentiation of ADSCs by up-regulating CREB1 and its phosphorylation.

Effect of Erxian Decoction-containing serum on H_2O_2-induced proliferation and osteogenic differentiation of MC3T3-E1 cells via BK channels / 中国中药杂志

This study aimed to investigate the effects of Erxian Decoction(EXD)-containing serum on the proliferation and osteogenic differentiation of MC3T3-E1 cells under oxidative stress through BK channels. The oxidative stress model was induced in MC3T3-E1 cells by H_2O_2, and 3 mmol·L~(-1) tetraethylammonium(TEA) chloride was used to block the BK channels in MC3T3-E1 cells. MC3T3-E1 cells were divided into a control group, a model group, an EXD group, a TEA group, and a TEA+EXD group. After MC3T3-E1 cells were treated with corresponding drugs for 2 days, 700 μmol·L~(-1) H_2O_2 was added for treatment for another 2 hours. CCK-8 assay was used to detect cell proliferation activity. The alkaline phosphatase(ALP) assay kit was used to detect the ALP activity of cells. Western blot and real-time fluorescence-based quantitative PCR(RT-qPCR) were used to detect protein and mRNA expression, respectively. Alizarin red staining was used to detect the mineralization area of osteoblasts. The results showed that compared with the control group, the model group showed significantly blunted cell proliferation activity and ALP activity, reduced expression of BK channel α subunit(BKα), collagen Ⅰ(COL1), bone morphogenetic protein 2(BMP2), osteoprotegerin(OPG), and phosphorylated Akt, decreased mRNA expression levels of Runt-related transcription factor 2(RUNX2), BMP2, and OPG, and declining area of calcium nodules. EXD-containing serum could significantly potentiate the cell proliferation activity and ALP activity, up-regulate the protein expression of BKα, COL1, BMP2, OPG, and phosphorylated Akt, and forkhead box protein O1(FoxO1), promote the mRNA expression of RUNX2, BMP2, and OPG, and enlarge the area of calcium nodules. However, BK channel blockage by TEA reversed the effects of EXD-containing serum in promoting the protein expression of BKα, COL1, BMP2, OPG, and phosphorylated Akt and FoxO1, increasing the mRNA expression of RUNX2, BMP2, and OPG, and enlarging the area of calcium nodules. EXD-containing serum could improve the proliferation activity, osteogenic differentiation, and mineralization ability of MC3T3-E1 cells under oxidative stress, which might be related to the regulation of BK channels and downstream Akt/FoxO1 signaling pathway.

Degradable hydrogel fibers encapsulate and deliver metformin and periodontal ligament stem cells for dental and periodontal regeneration

Abstract Human periodontal ligament stem cells (hPDLSCs) are promising cells for dental and periodontal regeneration. Objective This study aimed to develop novel alginate-fibrin fibers that encapsulates hPDLSCs and metformin, to investigate the effect of metformin on the osteogenic differentiation of hPDLSCs, and to determine the regulatory role of the Shh/Gli1 signaling pathway in the metformin-induced osteogenic differentiation of hPDLSCs for the first time. Methodology CCK8 assay was used to evaluate hPDLSCs. Alkaline phosphatase (ALP) staining, alizarin red S staining, and the expression of osteogenic genes were evaluated. Metformin and hPDLSCs were encapsulated in alginate-fibrinogen solutions, which were injected to form alginate-fibrin fibers. The activation of Shh/Gli1 signaling pathway was examined using qRT-PCR and western blot. A mechanistic study was conducted by inhibiting the Shh/Gli1 pathway using GANT61. Results The administration of 50 μM metformin resulted in a significant upregulation of osteogenic gene expression in hPDLSCs by 1.4-fold compared to the osteogenic induction group (P < 0.01), including ALP and runt-related transcription factor-2 (RUNX2). Furthermore, metformin increased ALP activity by 1.7-fold and bone mineral nodule formation by 2.6-fold (P<0.001). We observed that hPDLSCs proliferated with the degradation of alginate-fibrin fibers, and metformin induced their differentiation into the osteogenic lineage. Metformin also promoted the osteogenic differentiation of hPDLSCs by upregulating the Shh/Gli1 signaling pathway by 3- to 6- fold compared to the osteogenic induction group (P<0.001). The osteogenic differentiation ability of hPDLSCs were decreased 1.3- to 1.6-fold when the Shh/Gli1 pathway was inhibited, according to ALP staining and alizarin red S staining (P<0.01). Conclusions Metformin enhanced the osteogenic differentiation of hPDLSCs via the Shh/Gli1 signaling pathway. Degradable alginate-fibrin hydrogel fibers encapsulating hPDLSCs and metformin have significant potential for use in dental and periodontal tissue engineering applications. Clinical Significance Alginate-fibrin fibers encapsulating hPDLSCs and metformin have a great potential for use in the treatment of maxillofacial bone defects caused by trauma, tumors, and tooth extraction. Additionally, they may facilitate the regeneration of periodontal tissue in patients with periodontitis.

Red light-emitting diode light mediated by the KEAP1-NRF2/HO-1 pathway induces osteogenic differentiation and attenuates the oxidative stress damage of human periodontal ligament stem cells induced by high glucose / 口腔疾病防治

Objective@# To explore the effects of red LED light mediated by the Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (KEAP1-NRF2/HO-1) pathway on osteogenic differentiation and oxidative stress damage of human periodontal ligament stem cells (hPDLSCs) induced by high glucose, which provides a basis for the application of red light-emitting diode (LED) light in cell antioxidative damage.@*Methods@#hPDLSCs were identified by flow cytometric analysis, alkaline phosphatase (ALP) staining and Alizarin red-S staining; hPDLSCs were pretreated in a high glucose environment for 48 hours and irradiated with 1, 3, or 5 J/cm2 red LED light. A CCK-8 assay was performed to choose the radiant exposure that had the strongest effect on promoting the cell proliferation rate for subsequent experiments. hPDLSCs were divided into a control group, a high glucose group and a high glucose+light exposure group. ALP staining, ALP activity, Alizarin red-S staining and quantitative calcified nodules were used to detect the osteogenic differentiation of hPDLSCs; qRT-PCR and Western blot were used to detect the gene and protein expression levels of ALP, runt-related transcription factor 2 (RUNX2) and osterix (OSX); the relative mRNA expression levels of antioxidant enzyme-related genes superoxide dismutase 2 (SOD2) and catalase (CAT) in hPDLSCs were detected by qRT-PCR; reactive oxygen species (ROS) levels were detected by fluorescence microscopy and flow cytometry; the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels in cell supernatants were detected by ELISA; the NRF2-specific inhibitor ML385 was used to inhibit the NRF2 pathway; ALP staining and ALP activity were used to detect the markers of early osteogenic differentiation; qRT-PCR was used to detect the gene expression of ALP, RUNX2 and OSX; and the protein expression levels of KEAP1, NRF2 and HO-1 were detected by Western blot.@*Results @# Identified, and irradiant exposure of 5 J/cm2 was chosen for subsequent experiments. Red LED light irradiation (5 J/cm2) improved the osteogenic differentiation of hPDLSCs induced by high glucose (P<0.05), increased the mRNA and protein levels of ALP, RUNX2 and OSX (P<0.05), upregulated the mRNA expression levels of SOD2 and CAT (P<0.05), reduced the levels of ROS (P<0.05), and reduced TNF-α and IL-1β levels in the cell supernatants (P<0.05). When ML385 was added to inhibit the NRF2 pathway, the ALP activity of cells was decreased (P<0.05); the gene expression levels of ALP, RUNX2 and OSX were downregulated (P<0.05); the protein level of KEAP1 was upregulated (P<0.05); and the protein levels of NRF2 and HO-1 were downregulated (P<0.05)@*Conclusion@#Red LED light may promote the proliferation and osteoblastic differentiation of hPDLSCs induced by high glucose through the KEAP1-NRF2/HO-1 pathway and reduce the oxidative stress damage to hPDLSCs induced by high glucose.

Terpine-4-ol on inhibiting vascular smooth muscle cell calcification by improving mitochondrial dynamics / 药学学报

The aim of this study was to investigate the role and mechanism of terpinen-4-ol (T4O) on high glucose (HG) -induced calcification in vascular smooth muscle cell (VSMC). To investigate the role of T4O on HG-induced calcium deposition, osteogenic phenotypic transformation and mitochondrial dynamics in VSMC, Mdivi-1, a mitochondrial dynamin-related protein 1 (Drp-1) inhibitor, was used to analyze the correlation between mitochondrial dynamics and VSMC calcification and the role of T4O. Alizarin red S staining was used to observe calcium salt deposition and flow cytometry to detect intracellular Ca2+ content; Western blot and immunofluorescence were used to detect the expression of phenotypic switching-related markers α-smooth muscle actin (α-SMA), bone morphogenetic protein 2 (BMP2) and Runt related transcription factor 2 (Runx2), and mitochondrial dynamics-related markers mitofusin 1 (MFN1), mitofusin 2 (MFN2) and Drp-1. The results showed that low and high doses of T4O could inhibit HG-induced down-regulation of α-SMA, MFN1 and MFN2 expression levels, and up-regulation of BMP2, Runx2 and Drp-1 expression levels, reduce intracellular Ca2+ content and calcium salt deposition, and effectively inhibit HG-induced VSMC calcification and mitochondrial dynamics disorders. The T4O group, Mdivi-1 group and T4O+Mdivi-1 group were able to up-regulate the expression levels of HG-induced α-SMA, MFN1 and MFN2, down-regulate the protein expression levels of BMP2, Runx2 and Drp-1, and inhibit calcium salt deposition, and there was no significant difference between the above indexes in the T4O and T4O+Mdivi-1 groups. The above findings suggest that T4O can inhibit the expression level of Drp-1, regulate the disturbance of mitochondrial dynamics, and suppress HG-induced VSMC calcification.

Chinese Medicine Regulates Signaling Pathways Related to Proliferation and Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells： A Review / 中国实验方剂学杂志

Bone marrow mesenchymal stem cells （BMSCs） are derived from stem cells isolated from bone marrow and have the potential for multidirectional differentiation and self-renewal. Under certain conditions， BMSCs can be induced to differentiate into osteoblast （OB）， chondrocyte， adipocyte， fibroblast， etc. BMSCs play an important role in maintaining the stability of bone structure and balancing bone metabolism. Promoting the proliferation of BMSCs and inducing their differentiation into OB of great significance for the clinical prevention and treatment of osteoporosis， bone defects， fracture healing， and other diseases. Because the proliferation and osteogenic differentiation of BMSCs are complex processes controlled by multiple genes and regulated by multiple signal transduction pathways， traditional Chinese medicine （TCM） happens to have the advantages of multi-bioactive component， multi-target， and multi-pathway synergism， which can affect the proliferation and differentiation of BMSCs through multiple channels and induce the proliferation of BMSCs. The transcription and expression of genes related to osteogenesis can be enhanced to promote the differentiation of BMSCs into OB， so as to achieve the purpose of preventing and treating osteoporosis， bone defects， and other bone diseases. Based on the literature on the intervention of TCM monomers and compounds in the proliferation and osteogenic differentiation of BMSCs， this study reviewed TCM monomers and compounds in promoting the proliferation and osteogenic differentiation of BMSCs by regulating secreted glycoprotein （Wnt）， neurogenic locus notch homolog protein （Notch）， mitogen-activated protein kinase （MAPK）， phosphatidylinositol-3 kinase （PI3K） /protein kinase B （Akt）， bone morphogenetic protein （BMP）/Smad， Janus kinase （JAK）/signal transducer and activator of transcription protein （STAT）， osteoprotegerin （OPG）/receptor activator of nuclear factor-kappa B （RANK）/RANK ligand （RANKL）， and other signaling pathways to provide new ideas for the research and clinical application of Chinese medicine in the prevention and treatment of orthopedic diseases.

Assessment of Proliferation, Clonogenic Assay, and Osteogenic Differentiation of Human Periodontal Ligament Stem Cells Following Application of Orthodontic Forces

Context: The proliferation and differentiation of human periodontal ligament stem cells (hPDLSC) into other cell types are also mediated by mechanical stresses; they might offer therapeutic benefits in tissue regeneration and angiogenesis. Objectives: The study was planned to assess the proliferation, clonogenic potential, and osteogenic differentiation of human periodontal ligament stem cells (PDLSC) following the application of light and heavy orthodontic forces. Materials and Methods: A couple forces of 50 gm (light force) were applied on the 1st premolar on the one side and 250 gm (heavy force) on the contralateral side in the upper arch of patients requiring orthodontic treatment with extraction of all 1st premolars. After 30 days, periodontal tissues were scrapped from extracted teeth for the establishment of PDLSC in vitro. PDLC from the lower premolar teeth where no orthodontic force was applied acted as the control group. Morphology, viability, proliferating rate and population doubling time, clonogenicity, and alkaline phosphatase activity were analysed. Result: The osteogenic potential was confirmed by Alizarin red staining and the expression of the osteogenic markers by qRT?PCR. The morphology, growth kinetics, potency, and osteogenic lineage characteristics inferred the application of high force reduced the proliferative ability and osteogenesis of PDLSC, though the difference was not significant. Conclusion: The established PDLSCs demonstrated their MSC?like properties based on morphology, growth kinetics, colony forming ability, and AP activity. The culture?expanded PDLSCs showed their differentiation potential into osteocytes. The application of high force reduced the proliferative ability and osteogenesis of PDLSCs, variations were not significant.differentiation

Effects of fluoride exposure on proliferation, apoptosis and osteogenic differentiation of mouse bone marrow mesenchymal stem cells / 中华地方病学杂志

Objective:To investigate the effects of fluoride exposure on proliferation, apoptosis and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in mice.Methods:BMSCs were isolated and cultured from femur bone marrow of C57BL/6 mice (6 - 8 weeks). The cells in passage 3 were used to detect the surface markers of stem cells by flow cytometry. The cells were cultured in media with a final fluoride concentration of 0.0, 0.1, 1.0, 5.0, 10.0, 15.0, 20.0 and 40.0 mg/L, respectively. The effects of different fluoride concentrations on BMSCs cell proliferation (CCK8 method), apoptosis (flow cytometry analysis), osteogenic differentiation ability [alizarin red and alkaline phosphatase (ALP) staining] were detected. Western blot was applied to detect the levels of apoptosis-related proteins [poly ADP-ribose polymerase (PARP)], mitogen-activated protein kinase (MAPK) pathway member proteins [extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun amino-terminal kinase (JNK), p38 and phosphorylated ERK, JNK, p38 (p-ERK, p-JNK, p-p38)], osteogenic differentiation-related protein [Runt-related transcription factor 2 (Runx2), ALP] and Wnt/β-catenin pathway member proteins [glycogen synthase kinase-3β (GSK3β), phosphorylated GSK3β (p-GSK3β) and β-catenin]. Immunocytofluorescense staining was applied to evaluate the expression levels of p-GSK3β and β-catenin. The two pathways (MAPK and Wnt/β-catenin) were blocked by SP600125 and DKK-1, respectively, to testify their involvement in mechanisms of apoptosis and osteogenic differentiation.Results:The mouse BMSCs were successfully isolated and cultured. Flow cytometry analysis showed that the mesenchymal stem cell surface biomarkers (CD73, CD90 and CD105) were positively expressed. The comparison of cell proliferation at three time points (24, 48 and 72 h) in each concentration group was statistically significant ( F = 65.36, 160.04 and 365.32, P < 0.001), and the comparison of early apoptosis (24 h) in each concentration group was statistically significant ( F = 214.04, P < 0.001); compared with the 0.0 mg/L group, the cell proliferation in 15.0, 20.0 and 40.0 mg/L groups decreased, and the early apoptosis rate in 10.0, 15.0 and 20.0 mg/L groups increased ( P < 0.05). When cells were treated with 15.0 mg/L fluoride for 0 - 24 h, the p-JNK/JNK ratio was higher at 2, 4, 8, 12, 18 and 24 h compared with that at 0 min ( P < 0.05); compared with the fluoride group (15.0 mg/L), the early apoptosis rate of cells after SP600125 block decreased ( P < 0.05), and the protein expression levels of PARP and p-JNK decreased ( P < 0.05). After osteogenic induction, compared with the 0.0 mg/L group, in 0.1 and 1.0 mg/L groups ALP staining was enhanced and the number of calcified nodules increased, and the protein expression levels of Runx2 and ALP in the 0.1 and 1.0 mg/L groups were higher ( P < 0.05). After osteogenic induction, compared with the 0.0 mg/L group, the p-GSK3β/GSK3β ratio and β-catenin protein level were significantly higher in the 0.1 and 1.0 mg/L groups ( P < 0.05); and compared with the fluoride group (1.0 mg/L), addition of DKK-1 significantly decreased the protein expression levels of p-GSK3β and β-catenin and reduced the nuclear entry of β-catenin, and ALP staining decreased and the number of calcified nodules decreased. Conclusions:High concentration of fluoride (> 10.0 mg/L) inhibits the proliferation and promotes apoptosis of BMSCs, while low concentration of fluoride (0.1, 1.0 mg/L) promotes osteogenic differentiation. The MAPK/JNK pathway and the classical Wnt pathway are involved in the above cellular processes, respectively.

Research progress on metformin in the prevention and treatment for oral diseases / 口腔疾病防治

@#Metformin is currently the first-line drug for the treatment of diabetes. In addition to its hypoglycemic effect, it has also been found to have other potential effects, such as anti-inflammatory, odontogenic differentiation-promoting, osteogenic differentiation-promoting, and antitumor effects. Previous studies have shown that metformin can promote the healing of periapical lesions, and its mechanism may be related to the promotion of osteogenic differentiation and the induction of dental pulp cell differentiation by activation of adenylate-activated protein kinase by dimethyldiphosphate. Clinical indexes, such as the probing depth, attachment loss level and probing bleeding index, were significantly improved in patients with periodontitis treated with metformin, which may play a role in the prevention and treatment of periodontal disease by promoting the proliferation, migration and osteogenic differentiation of periodontal ligament stem cells. Metformin has been proven to inhibit the growth and proliferation of tumor cells and plays an important role in the prevention and treatment of oral tumors such as oral squamous cell carcinoma. At present, research remains in the in vitro and animal experimental stage, and the related mechanism needs to be further explored. Clinical trials remain in the evaluation of clinical indicators, so large-scale, long-term, multicenter, randomized controlled clinical trials need to be further developed

CCDC134 regulates the osteogenic differentiation of human dental pulp stem cells / 口腔疾病防治

Objective @#To study the regulatory effect of coiled-coil domain containing 134 (CCDC134) on the osteogenic differentiation of human dental pulp stem cells (hDPSCs).@*Methods @# HDPSCs were isolated and cultured from dental pulp tissue and transfected with NC-CCDC134, shCCDC134 and CCDC134 lentiviruses. They were divided into the control group, negative control group, CCDC134 downregulation (shCCDC134) group and CCDC134 overexpression (CCDC134) group. Surface markers of hDPSCs (Stro-1, CD105, CD34, CD45) were detected by flow cytometry; colony formation was analyzed by toluidine blue staining; ALP expression was estimated by ALP staining; mineralized nodule formation was evaluated by alizarin red staining; lipid droplet formation was examined by oil red staining; and gene and protein expression of CCDC134, Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), bone morphogenetic protein-2 (BMP-2), and mothers against decapentaplegic homolog 1 (SMAD1) was detected by qPCR and western blot, respectively. Further, a BMP-2 activator (BMP-2) and inhibitor (Dorsomorphin) were used to down-regulate and up-regulate CCDC134, respectively (shCCDC134, shCCDC134+BMP-2, CCDC134, CCDC134+Dorsomorphin), in hDPSCs. The hDPSC aggregates were subcutaneously transplanted into nude mice for 2 months, and new bone formation was detected by H&E staining. The BMP-2/SMAD1 signaling in each group was detected by qPCR.@*Results@#hDPSCs showed high expression of mesenchymal markers and low expression of hematopoietic markers. Compared with the control group, the expression of CCDC134 was increased in the osteogenic-induced hDPSCs (P < 0.05). Compared with the negative control group, the expression of CCDC134 was decreased in the shCCDC134 group, whereas it was increased in the CCDC134 group (P < 0.05). The mineralized nodules, osteogenic genes and proteins in the shCCDC134 group were decreased (P < 0.05), while they were increased in the CCDC134 group (P < 0.05). The expression of BMP-2/SMAD1 signaling decreased in the shCCDC134 group, while it increased in the CCDC134 group (P < 0.05). Compared to the shCCDC134 group, osteogenic genes and proteins increased in the shCCDC134+BMP-2 group, and subcutaneous new bone formation increased in nude mice (P < 0.05). The indexes of the CCDC134+Dorsomorphin group decreased compared with the CCDC134 group (P < 0.05).@*Conclusion@#CCDC134 promotes the osteogenic differentiation of hDPSCs by regulating the BMP-2/SMAD1 signaling pathway.

Effect of silencing HDAC9 on the proliferation and differentiation of periodontal ligament stem cells / 口腔疾病防治

Objective @#To investigate the effect of silencing histone deacetylase 9 (HDAC9) expression on the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs).@*Methods@# PDLSCs were isolated, cultured and identified in vitro. An siRNA construct specific for HDAC9 was transfected into PDLSCs (siHDAC9 group), and a nontargeting siRNA was used as a control (siNC group). The interference effect was determined by qRT-PCR. The cell cycle progression of PDLSCs was detected using flow cytometry. The proliferation activity of PDLSCs was detected via CCK-8 assay. Western blotting was used to detect the protein expression of proliferating cell nuclear antigen (PCNA). The mRNA expression of runt-related transcription factor 2 (RUNX2) and alkaline phosphatase (ALP) was investigated by qRT-PCR. The protein expression of RUNX2 was detected by western blotting. In addition, the formation of mineralized nodules was assessed by alizarin red staining. @*Results@#Compared with that in the siNC group, the mRNA expression of HDAC9 in the siHDAC9 group was lower (P < 0.01). Moreover, compared with those in the siNC group, the proliferation index (P<0.01), proliferation activity (P<0.05) and protein expression of PCNA (P<0.01) in the siHDAC9 group were all increased. Compared with the siNC group, the siHDAC9 group exhibited higher mRNA expression of RUNX2 and ALP (P < 0.05), and the protein expression of RUNX2 showed the same results (P < 0.01). The results of alizarin red staining showed that compared to the siNC group, the siHDAC9 group formed more mineralized nodules.@* Conclusion@#Silencing HDAC9 expression can promote the proliferation and osteogenic differentiation of PDLSCs.