Fibroblasts inhibit osteogenesis by regulating nuclear-cytoplasmic shuttling of YAP in mesenchymal stem cells and secreting DKK1

Background Fibrous scars frequently form at the sites of bone nonunion when attempts to repair bone fractures have failed. However, the detailed mechanism by which fibroblasts, which are the main components of fibrous scars, impede osteogenesis remains largely unknown. Results In this study, we found that fibroblasts compete with osteogenesis in both human bone nonunion tissues and BMP2-induced ectopic osteogenesis in a mouse model. Fibroblasts could inhibit the osteoblastic differentiation of mesenchymal stem cells (MSCs) via direct and indirect cell competition. During this process, fibroblasts modulated the nuclear-cytoplasmic shuttling of YAP in MSCs. Knocking down YAP could inhibit osteoblast differentiation of MSCs, while overexpression of nuclear-localized YAP-5SA could reverse the inhibition of osteoblast differentiation of MSCs caused by fibroblasts. Furthermore, fibroblasts secreted DKK1, which further inhibited the formation of calcium nodules during the late stage of osteogenesis but did not affect the early stage of osteogenesis. Thus, fibroblasts could inhibit osteogenesis by regulating YAP localization in MSCs and secreting DKK1. Conclusions Our research revealed that fibroblasts could modulate the nuclear-cytoplasmic shuttling of YAP in MSCs, thereby inhibiting their osteoblast differentiation. Fibroblasts could also secrete DKK1, which inhibited calcium nodule formation at the late stage of osteogenesis.

Uso de microvibración e inhibidores de la catepsina K en tratamientos de regeneración ósea dental / Use of micro-vibration and cathepsin K inhibitors in dental bone regeneration treatments

Introducción: el hueso está en remodelación constante para mantener la estructura del esqueleto, tener un ciclo de resorción por los osteoclastos y formación de hueso nuevo a cargo de los osteoblastos; el hueso también es susceptible a enfermedades sistémicas, traumas, edad y trastornos genéticos que afectarán el remodelado óseo, produciendo una pérdida masiva de masa ósea regulado por hormonas, citocinas, enzimas, etcétera. El objetivo es realizar una revisión sistemática de artículos que muestren cambio o alteración al utilizar tratamientos con microvibraciones y farmacológicos sobre la catepsina K en el hueso alveolar. Material y métodos: para realizar una comparación entre la efectividad del tratamiento a base de microvibraciones y con inhibidores de la catepsina K, se realizó una revisión sistemática en nueve bases de datos (Wiley Online Library, PubMed, Google Academic, Scopus, ScienceDirect, SciELO, Medline, EBSCO y Springer Link). La población de estudio fueron ratas y ratones. Resultados: en este estudio se incluyeron 20 artículos cuya investigación se realizó en estudios clínicos. En los resultados podemos observar cómo todos los tratamientos de alguna forma mejoran el proceso de remodelado óseo. Es difícil comparar cuál de los tratamientos dentro de cada grupo es mejor que otro, debido a que los resultados expresados son cualitativos. Conclusión: acorde a los resultados expresados se opta por realizar un tratamiento con microvibraciones debido a que el uso de inhibidores de la catepsina K aún no se encuentra completamente desarrollado y no se comprenden sus consecuencias debido a su manera sistémica de actuar (AU)

Introduction: the bone is in constant remodeling to maintain the skeletal structure, having a cycle of resorption by osteoclasts and formation of new bone by osteoblasts, the bone is also susceptible to systemic diseases, trauma, age and genetic disorders that affect bone remodeling, producing a massive loss of bone mass regulated by hormones, cytokines, enzymes, etcetera. The objective is to perform a systematic review of articles that show a change or alteration when using micro-vibration and pharmacological treatments on cathepsin K in the alveolar bone. Material and methods: in order to make a comparison between the effectiveness of micro-vibration and cathepsin K inhibitor treatments, a systemic review was carried out in nine databases (Wiley Online Library, PubMed, Google Academic, Scopus, ScienceDirect, SciELO, Medline, EBSCO and Springer Link). The study population was rats and mice. Results: this study included 20 articles whose research was carried out in clinical studies. In the results we can see how all the treatments in some way improve the bone remodeling process, it is difficult to compare which treatment within each group is better than the other, because the results expressed are qualitative. Conclusion: according to the results expressed, it is decided that it is better to perform a treatment with micro vibrations because the use of cathepsin K inhibitors are not yet fully developed and their consequences are not understood due to their systemic way of acting (AU)

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.

Effect of the chicken zp1 gene on osteoblast mineralization / 生物工程学报

The aim of this study was to clone the chicken zp1 gene encoding zona pellucida 1 (Zp1) and investigate its tissues expression profile and its effect on osteoblast mineralization. The expression level of zp1 was quantified in various tissues of laying hens and in the tibia of the pre- and post-sexual maturity by RT-qPCR. Zp1 overexpressed vector was transfected into chicken calvarial osteoblasts which were induced differentiation for 8 days, and the extracellular mineral and the expression of mineralization-related genes were detected. The full-length chicken zp1 gene is 3 045 bp, encoding 958 amino acids residuals, and has two N-glycosylation sites. The highest expression level of the zp1 gene was found in the liver, followed by the tibia and yolk membrane, while no expression was detected in the heart and eggshell gland. Compared with the pre-sexual maturity hens, the concentration of estrogen (E2) in plasma, the content of glycosaminoglycan (GAG) and the expression level of the zp1 gene in the tibia with post-sexual maturity were higher. The extracellular matrix and the level of osteoblast mineralization-related genes showed a significantly upregulated expression in chicken calvarial osteoblasts with Zp1 overexpressed and addition of estrogen. The expression of the zp1 gene is tissue-specific and positively regulated osteoblast mineralization under the action of estrogen, laying the foundation for elucidating the functional properties of Zp1 in chicken bones during the egg production period.

Mechanism of Artemisia annua L. in GIOP with kidney-yin deficiency based on network pharmacology / 药学实践杂志

Objective To predict and preliminarily verify the potential targets and related signaling pathways of Artemisia annua L. in treating glucocorticoid-induced osteoporosis (GIOP) with kidney-yin deficiency by network pharmacology and in vitro experiments. Methods The pharmacological targets of Artemisia annua L. were obtained from TCMSP database and were converted to gene names through Uniprot database. The target genes of GIOP with kidney-yin deficiency were obtained from GeneCards database, OMIM database and Drugbank database, and the common target genes were obtained by cross analysis with drug target gene. Protein-protein interaction (PPI) network was constructed by String database, and visualization analysis and core targets screening were performed by Cytoscape 3.9.0. All common targets were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis through Metascape database. Finally, the prediction results were verified by in vitro experiments. Results Ninety-eight targets of Artemisia annua L. to GIOP with kidney-yin deficiency were screened, including 17 core genes. The results of GO and KEGG functional enrichment analysis indicated that Artemisia annua L. treating GIOP with kidney-yin deficiency was related to biological processes such as hormonal response, positive regulation of cell death and extracellular stimulation response, et al, as well as signaling pathways such as PI3K/AKT, AGE/RAGE, MAPK and IL-17 et al. The number of genes enriched in PI3K/AKT signaling pathway was the largest. In vitro experiment results showed that Artemisia annua L. promoted the proliferation of osteoblasts damaged by dexamethasone (DEX), increased alkaline phosphatase activity, activated PI3K/AKT pathway, and promoted the phosphorylation of AKT. Conclusion Artemisia annua L. treating GIOP with kidney-yin deficiency has the characteristics of multi-targets and multi-pathway, which could promote the proliferation and differentiation of osteoblasts through multiple pathways. The PI3K/AKT signaling pathway is an important pathway. Artemisia annua L. treating GIOP with kidney-yin deficiency might be related to its ability to promote the PI3K/AKT signaling pathway and promote the phosphorylation of AKT.

Role and diagnostic value of miRNA-205 on vascular calcification in patients with chronic kidney disease / 中华肾脏病杂志

Objective:To investigate the role and diagnostic value of miRNA-205 in chronic kidney disease (CKD) patients with vascular calcification.Methods:It was divided into in vitro cell experiment and retrospective cohort study. In vitro experiments were conducted by using rat thoracic aortic smooth muscle cells. Alizarin red staining and calcium content detection were used to detect the calcification of vascular smooth muscle cells (VSMCs). Alkaline phosphatase (ALP) test kit was used to measure ALP activity. Western blotting was used to detect the protein expression levels of osteogenic transcription factors runt-related transcription factor 2 (Runx2), α smooth muscle actin (α-SMA) and smooth muscle-22α (SM-22α) in VSMCs. qRT-PCR was used to detect miRNA-205 and Runx2 expression levels. The double luciferase reporter gene assay was used to verify the targeted relationship between miRNA-205 and Runx2. The non-dialysis patients with CKD 3-5 stage from June 2020 to January 2021 in the Department of Nephrology of Fourth Hospital, Hebei Medical University were selected. According to coronary artery calcium score (CACs), the patients were divided into non-calcification group (CACs=0), mild-moderate calcification group (0<CACs≤400), and severe calcification group (CACs > 400). Spearman correlation analysis was used to analyze the correlation between miRNA-205 and Runx2 and vascular calcification. Logistic regression model and receiver operating characteristic (ROC) curve analysis were used to analyze the ability of miRNA-205 to predict the vascular calcification in patients with CKD. Results:(1)Compared with the control group, calcium nodules were more, and the calcium content, ALP activity and Runx2 protein level were higher, and the expression levels of miRNA-205, α-SMA and SM-22α were significantly lower in high phosphorus group (all P<0.05). Overexpression of miRNA-205 significantly reduced the calcification of VSMCs and Runx2 protein level, and increased the protein levels of α-SMA and SM-22α (all P<0.05). miRNA-205-5p reduced the activity of luciferase in the wild-type Runx2-3'-end non-coding region plasmid. (2) Eighty CKD patients were enrolled, with age of (57.50±14.93) years old and 49 males (61.3%). The results of comparison of miRNA-205 and Runx2 expression levels in non-calcification group ( n=26), mild- moderate calcification group ( n=30) and severe calcification group ( n=24) showed that, the higher degree of calcification, the lower miRNA-205 expression level and the higher Runx2 mRNA expression level (all P<0.05). miRNA-205 was negatively correlated with CACs ( r=-0.50, P<0.01) and Runx2 was positively correlated with CACs ( r=0.55, P<0.01). Multivariate logistic regression analysis results suggested that miRNA-205 ( OR=0.451, 95% CI 0.122-0.873) was an independent influencing factor of vascular calcification in CKD patients. The area under the ROC curve of miRNA-205 and miRNA-205 combined with Runx2 for predicting vascular calcification were 0.796 (95% CI 0.697-0.859) and 0.924 (95% CI 0.866-0.982), respectively. Conclusions:miRNA-205 inhibits vascular calcification by targeting Runx2 to negatively regulate osteogenetic phenotype transformation of VSMCs and is expected to be an early diagnostic marker of vascular calcification in CKD patients.

Mir-199a-3p Mediates Fluid Shear Stress-Induced Osteoblast Proliferation by Targeting CABLES-1 / 医用生物力学

Objective To explore the role of miR-199a-3p in osteoblast proliferation induced by fluid shear stress (FSS) and the potential molecular mechanism. Methods Osteoblast MC3T3-E1 was treated with 1. 2 Pa FSS with time gradients of 0, 15, 30, 45, 60, 75 and 90 min, respectively. MC3T3-E1 cells were transfected with miR-199a-3p mimic or miR-199a-3p inhibitor. MC3T3-E1 cells were transfected with miR-199a-3p mimic and itsnegative control and then treated with 1. 2 Pa FSS for 45 min. The pc DNA NC, pc DNA-CABLES -1, si RNA NC and si RNA CABLES-1 were transfected into MC3T3-E1 cells. The pc DNA-CABLES-1 and mir-199a-3p mimic and SI NA-cables-1 and miR-199a-3p inhibitor were co-transfected, respectively. Cell activity was detected by CCK-8 assay. Real-time quantitative PCR (RT-qPCR) was used to detect expression levels of CABLES-1, miR-199a-3p, CDK 6, Cyclin D1 and PCNA. Luciferase reporting assay was used to detect targeting relationship between CABLES-1 and miR-199a-3p. Immunofluorescence was used to detect protein expression of CABLES-1.Western blot was used to detect protein expression of CABLES-1, CDK 6, PCNA and Cyclin D1. Results Mir- 199a-3p in MC3T3-E1 cells was significantly down-regulated by FSS. Over-expressed miR-199a-3p inhibitedosteoblast proliferation, and down-regulated miR-199a-3p expression promoted osteoblast proliferation. miR-199a- 3p could reverse the FSS-induced proliferation in osteoblasts. Dual luciferase assay showed that miR-199a-3p targeted to CABLES-1 and over-expressed miR-199a-3p inhibited expression of CBALES-1 protein. CABLES-1 could promote proliferation of osteoblasts. miR-199a-3p inhibited osteoblast proliferation induced by FSS through CABLES-1. Conclusions FSS-induced osteoblast proliferation can be realized by down-regulated miR-199a-3p expression via targeting CABLES-1. The findings in this study provide new direction for researches on mechanism of FSS-induced osteoblast proliferation, as well as new ideas for future research on clinical application of mechanical loading in the treatment of bone and joint diseases.

Effect and mechanism of Bajitianwan on preventing D-galactose-induced osteoblast bone loss / 药学实践杂志

Objective To explore the effect and mechanism of Bajitianwan on preventing D-galactose (D-gal)-induced osteoblast bone loss. Methods Osteoblasts isolated from 24 h old Wistar rats were injured by D-gal and intervened with Bajitianwan extract. The osteoblastic proliferation and differentiation were determined by MTT and alkaline phosphatase (ALP), respectively. The cell reactive oxygen species (ROS) levels were detected by DCFH-DA fluorescent probes. The expression of cellular oxidation-related protein nuclear factor erythroid 2-related factor 2 (Nrf2), phosphorylated protein kinase B (p-AKT), protein kinase B (AKT), heme oxygenase-1 (HO-1), and NADPH quinone oxidoreductase 1 (NQO1) were detected by Western blotting. The intranuclear expression of Nrf2 protein was measured by immunofluorescence. Results Bajitianwan extract had significantly increased the osteoblastic proliferation and differentiation, and significantly reduced the intracellular ROS level. Bajitianwan extract had activated the PI3K/AKT pathway via activating the phosphorylation of AKT in osteoblasts, and promoted NQO1 and HO-1 expression. In addition, Bajitianwan had significantly promoted the expression of Nrf2 in the nucleus of osteoblasts, activating Nrf2 signaling pathway, and further promoted bone formation. Conclusion This study confirmed that Bajitianwan could prevent D-gal injured osteoblastic bone loss for the first time. The mechanism might be related to the regulation of oxidative stress associated PI3K/AKT and Nrf2 signaling pathway.

Role of Oxidative Stress in Osteoporosis and Treatment by Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

Osteoporosis （OP） is a systemic metabolic bone disease. Amid population aging， OP has become a major health problem for the middle-aged and the elderly in China. Aging， iron load， and estrogen deficiency break the balance between oxidation and antioxidant systems， and the increase of reactive oxygen species mediates oxidative stress to damage DNA， lipids， proteins and other macromolecules， thus accelerating cell apoptosis and inducing OP， obesity， and neurodegenerative disorders. It has been found that oxidative stress is of great significance in the pathogenesis of OP. Oxidative stress regulates the signaling pathways， cytokines， and proteins related to the mesenchymal stem cells， osteoblasts， and osteoclasts， thereby weakening the osteogenic differentiation of mesenchymal stem cells， inhibiting osteoblast mineralization， and promoting the activation， proliferation， and maturation of osteoclasts. As a result， the dynamic imbalance between bone resorption and bone formation occurs， influencing bone remodeling and promoting the progression of OP. At the moment， anti-bone resorption drugs， bone formation-promoting drugs， and hormones are mainly used in clinical settings in western medicine. However， due to the long treatment cycle and the occurrence of serious gastrointestinal reactions， hypocalcemia， osteonecrosis， and others， patients show poor compliance and thus the effect is not as expected. Traditional Chinese medicine （TCM） demonstrates remarkable effect on OP attributing to the multi-pathway and multi-target characteristics. With low price and few adverse reactions， TCM is widely applied in clinical practice in comparison with western medicine. TCM has unique advantages in the treatment of OP by regulating oxidative stress. It exerts the therapeutic effect on OP by modulating different signaling pathways， providing new mindset for the treatment of this disease. Therefore， through literature research， this study summarized the research on mechanism of oxidative stress in OP and the treatment by TCM， which is expected to lay a foundation for further research.

Advances on pentraxin 3 in osteoporosis and fracture healing / 中国骨伤

Pentaxin 3 (PTX3), as a multifunctional glycoprotein, plays an important role in regulating inflammatory response, promoting tissue repair, inducing ectopic calcification and maintaining bone homeostasis. The effect of PTX3 on bone mineral density (BMD) may be affected by many factors. In PTX3 knockout mice and osteoporosis (OP) patients, the deletion of PTX3 will lead to decrease of BMD. In Korean community "Dong-gu study", it was found that plasma PTX3 was negatively correlated with BMD of femoral neck in male elderly patients. In terms of bone related cells, PTX3 plays an important role in maintaining the phenotype and function of osteoblasts (OB) in OP state;for osteoclast (OC), PTX3 in inflammatory state could stimulate nuclear factor κ receptor activator of nuclear factor-κB ligand (RANKL) production and its combination with TNF-stimulated gene 6(TSG-6) could improve activity of osteoclasts and promote bone resorption;for mesenchymal stem cells (MSCs), PTX3 could promote osteogenic differentiation of MSCs through PI3K/Akt signaling pathway. In recent years, the role of PTX3 as a new bone metabolism regulator in OP and fracture healing has been gradually concerned by scholars. In OP patients, PTX3 regulates bone mass mainly by promoting bone regeneration. In the process of fracture healing, PTX3 promotes fracture healing by coordinating bone regeneration and bone resorption to maintain bone homeostasis. In view of the above biological characteristics, PTX3 is expected to become a new target for the diagnosis and treatment of OP and other age-related bone diseases and fracture healing.

Dose-dependent effects of neem crude extract on human dental pulp cell and murine osteoblast viability and mineralization

Abstract Neem has been used as a medicine due to its beneficial properties such as anti-microbial effects. Neem products for oral application are on the rise. Before recommendation for therapeutic use in human, its effects on cellular activities need to be examined. Therefore, the aim of this study was to test the effects of the ethanolic neem crude extract on dental pulp cells and osteoblasts in terms of cell viability, mineralization, and gene expressions. The ethanolic neem extract derived from dry neem leaves was subjected to chemical identification using GC-MS. Human dental pulp stem cells (hDPSCs) and pre-osteoblasts (MC3T3) were treated with various concentrations of the neem crude extract. Cell viability, mineralization, and gene expressions were investigated by MTT assay, real-time PCR, and alizarin red S assay, respectively. Statistical analysis was performed by one-way ANOVA followed by Dunnett test. GC-MS detected several substance groups such as sesquiterpene. Low to moderate doses of the neem crude extract (4 - 16 µg/ml) did not affect hDPSC and MC3T3 viability, while 62.5 µg/ml of the neem extract decreased MC3T3 viability. High doses of the neem crude extract (250 - 1,000 µg/ml) significantly reduced viability of both cells. The neem crude extract at 1,000 µg/ml also decreased viability of differentiated hDPSC and MC3T3 and their mineralization. Furthermore, 4 µg/ml of neem inhibited viability of differentiated hDPSC. There is no statistical difference in gene expressions related to cell differentiation. In conclusion, the neem crude extract affected cell viability and mineralization. Cell viability altered differently depending on the doses, cell types, and cell stages. The neem crude extract did not affect cell differentiation. Screening of its effect in various aspects should be examined before the application for human use.

Resumo O Neem tem sido utilizado como medicamento devido às suas propriedades benéficas, tais como os efeitos antimicrobianos. Os produtos Neem para aplicação oral estão a aumentar. Antes da recomendação para uso terapêutico no ser humano, os seus efeitos nas atividades celulares precisam ser examinados. Por conseguinte, o objectivo deste estudo era testar os efeitos do extracto bruto de neem etanólico nas células de polpa dentária e osteoblastos em termos de viabilidade celular, mineralização e expressões genéticas. O extracto de neem etanólico derivado de folhas secas de neem foi sujeito a identificação química utilizando GC-MS. As células estaminais de polpa dentária humana (hDPSCs) e os pré-osteoblastos (MC3T3) foram tratados com várias concentrações do extrato bruto de neem. A viabilidade celular, mineralização, e expressões genéticas foram investigadas pelo ensaio MTT, PCR em tempo real, e o ensaio S vermelho de alizarina, respectivamente. A análise estatística foi realizada por ANOVA unidirecional seguida pelo teste Dunnett. O GC-MS detectou vários grupos de substâncias como o esquisterpeno. Doses baixas a moderadas do extracto bruto de neem (4 - 16 µg/ml) não afetaram a viabilidade do hDPSC e MC3T3, enquanto 62,5 µg/ml do extracto de neem diminuiu a viabilidade do MC3T3. Doses elevadas do extrato bruto de neem (250 - 1.000 µg/ml) reduziram significativamente a viabilidade de ambas as células. O extrato bruto de neem a 1.000 µg/ml também diminuiu a viabilidade de hDPSC e MC3T3 diferenciados e a sua mineralização. Além disso, 4 µg/ml de neem inibiu a viabilidade do hDPSC diferenciado. Não há diferença estatística nas expressões genéticas relacionadas com a diferenciação celular. Em conclusão, o extrato bruto do neem afetou a viabilidade celular e a mineralização. A viabilidade celular alterou-se diferentemente dependendo das doses, tipos de células, e fases celulares. O extrato bruto do neem não afetou a diferenciação celular. O rastreio do seu efeito em vários aspectos deve ser examinado antes da aplicação para uso humano.

The pivotal role of autophagy in bone cells:bone-related cell activity and bone metabolism / 中国组织工程研究

BACKGROUND:The importance of autophagy for maintaining cellular homeostasis and stress response has long been recognized.As a way for cells to selectively clear their damaged organelles to achieve the recycling of cellular components,autophagy has a pivotal role in bone metabolism.OBJECTIVE:To review the role and possible mechanisms of autophagy in regulating bone-related cell activity and function among bone marrow mesenchymal stem cells,osteoblasts,osteocytes,and osteoclasts.METHODS:PubMed was searched for studies related to autophagy using the keywords of "autophagy;bone marrow mesenchymal stem cells;osteoblasts;osteocytes;osteoclasts."RESULTS AND CONCLUSION:We finally included 84 papers.Autophagy plays an important role in bone metabolism.Autophagy is involved in maintaining the balance between mineralization and absorption,and then maintaining bone homeostasis.An appropriate autophagy inducer may also benefit bone remodeling.Abnormal autophagy can lead to disorders of bone balance,leading to diseases such as osteoporosis.We may prevent or treat bone-related diseases by regulating the level of autophagy as its function in maintaining the balance of mineralization and resorption in bone homeostasis.

Cyclic Stretch Promotes Migration of MC3T3-E1 Cells via Increasing Runx2 Expression / 医用生物力学

Objective To investigate the effects of cyclic stretch on migration of MC3T3-E1 cells and its related mechanism. Methods The strain loading system was used to stretch MC3T3-E1 cells cultured in vitro with 15% amplitude, to simulate the mechanical condition in vivo. The wound healing assay was used to detect the migration of MC3T3-E1 cells. Western blotting was used to test Runx2 expression. RNA interfering was used to decrease Runx2 expression. Results Cyclic mechanical stretch with 15% amplitude, 1.25 Hz frequency and lasting for 24 hours could promote the migration of MC3T3-E1 cells and increase the expression level of Runx2. Runx2 interference inhibited the migration of MC3T3-E1 cells in static culture condition. Interference with Runx2 expression in MC3T3-E1 cells could partially reduce the positive effect of cyclic mechanical stretch on cell migration. Conclusions Cyclic stretch can promote the migration of MC3T3-E1 cells, and Runx2 may play an important role in this process. This study provides experimental basis for finding innovative clinical treatment method to promote fracture healing.

Aqueous extract of freeze-dried Protaetia brevitarsis larvae promotes osteogenesis by activating β-catenin signaling

Objective: To investigate the effect of an aqueous extract of Protaetia brevitarsis (AEPB) on osteogenesis using preosteoblast MC3T3-E1 cells and zebrafish larvae. Methods: Flow cytometric analysis was used to measure the cytotoxicy. Alkaline phosphatase activity was detetmined using p-nitrophenyl phosphate as a substrate. Calcium deposition was detected using alizarin red staining along with osteogenic marker expression in preosteoblast MC3T3E1 cells. In addition, vertebral formation in zebrafish larvae was detected using calcein staining and osteogenic gene expression. Results: AEPB highly promoted the expression of osteogenic markers including runt-related transcription factor 2, osterix, and alkaline phosphatase, along with elevated levels of mineralization in MC3T3-E1 cells. Moreover, AEPB accelerated vertebral formation in zebrafish larvae accompanied by upregulated expression of osteogenic genes. FH535, an inhibitor of Wnt/β-catenin, suppressed AEPB-induced osteogenic gene expression and vertebral formation, indicating that AEPB stimulates osteogenesis by activating the Wnt/β-catenin signaling pathway. Conclusions: AEPB stimulates osteoblast differentiation and bone formation by activating β-catenin. Therefore, AEPB is a promising material that induces osteogenesis, and is useful for the treatment of bone resorption diseases.

Influence of titanium nanotubular surfaces, produced by anodization, on the behavior of osteogenic cells: in vitro evaluation / Influência da superfície nanotubular do titânio, produzido por anodização, no comportamento de células osteogênicas: avaliação in vitro

Objective: The objective of this study was to evaluate in vitro the influence of the anodized surface of Ti35Nb7Zr alloy on the behavior of osteogenic cells, for future application in biomedical implants. Material and Methods: For the development of this research, samples of commercially pure titanium (TiCp) and samples of Ti35Nb7Zr alloy were anodized, both were characterized by scanning electron microscopy (SEM) and were plated afterwards with human osteoblast-like cells (MG63 line) (2 x 104). Cell adhesion, cytotoxicity test, formation of mineralization nodules and a comet assay were also performed in different periods. The bottom of the plate was used as a control, without a sample. Results: SEM analysis showed that the topography of both samples presented surfaces covered by nanotubes. Cellular morphology exhibited spreading in both samples proposing an intimate cell- material liaison. After 3 days, the Ti35Nb7Zr group exhibited greater cell viability than the TiCp group (p<0.01). Regarding calcium content, there was no statistical difference between the anodized groups, but there was a difference between the experimental groups and the control group (p<0.01). In the comet assay, the percentage of DNA in the comet tail did not exhibit any significant difference (p>0.05) among the groups in the evaluated periods. Conclusion: It was concluded that this process of anodization was efficient to form nanotubes, as well as promote a positive influence on the behavior of osteogenic cells without promoting cell damage. (AU)

Objetivo: O objetivo deste estudo foi avaliar in vitro a influência da superfície anodizada da liga Ti35Nb7Zr no comportamento de células osteogênicas, para futura aplicação em implantes biomédicos. Material e Métodos: Para o desenvolvimento desta pesquisa, amostras de titânio comercialmente puro (TiCp) e amostras da liga Ti35Nb7Zr foram anodizadas, ambas foram caracterizadas por microscopia eletrônica de varredura (MEV) e posteriormente plaqueadas com células semelhantes a osteoblastos humanos (linha MG63) (2 x 104). Foram realizados em diferentes períodos a adesão celular, teste de citotoxicidade, formação de nódulos de mineralização e ensaio do cometa. O fundo da placa foi usado como controle, sem amostra. Resultados: A análise em MEV mostrou que a topografia de ambas as amostras apresentava superfícies cobertas por nanotubos. A morfologia celular exibiu espalhamento em ambas as amostras, propondo uma ligação íntima célula-material. Após 3 dias, o grupo Ti35Nb7Zr exibiu maior viabilidade celular do que o grupo TiCp (p<0.01). Em relação ao teor de cálcio, não houve diferença estatística entre os grupos anodizados, mas houve diferença entre os grupos experimentais e o grupo controle (p<0.01). No ensaio do cometa, a porcentagem de DNA na cauda do cometa não apresentou diferença significativa (p> 0.05) entre os grupos nos períodos avaliados. Conclusão:Concluiu-se que esse processo de anodização foi eficiente para formar nanotubos, além de promover uma influência positiva no comportamento das células osteogênicas sem promover dano celular. (AU)

Bone regeneration of induced pluripotent stem cells derived from peripheral blood cells in collagen sponge scaffolds

Abstract Stem cell-based regeneration therapy offers new therapeutic options for patients with bone defects because of significant advances in stem cell research. Although bone marrow mesenchymal stem cells are the ideal material for bone regeneration therapy using stem cell, they are difficult to obtain. Induced pluripotent stem cells (iPSCs) are now considered an attractive tool in bone tissue engineering. Recently, the efficiency of establishing iPSCs has been improved by the use of the Sendai virus vector, and it has become easier to establish iPSCs from several type of somatic cells. In our previous study, we reported a method to purify osteogenic cells from iPSCs. Objective: This study aimed to evaluate the osteogenic ability of iPSCs derived from peripheral blood cells. Methodology: Mononuclear cells (MNCs) were obtained from human peripheral blood. Subsequently, T cells were selectively obtained from these MNCs and iPSCs were established using Sendai virus vectors. Established iPSCs were evaluated by the expression of undifferentiated markers and teratoma formation assays. Osteoblasts were induced from these iPSCs and evaluated by the expression of osteoblast markers. Additionally, the induced osteoblasts were transplanted into rat critical size calvaria bone defect models with collagen sponge scaffolds. Samples were evaluated by radiographical and histological assessments. Results: Induced osteoblasts expressed several osteoblast-specific markers. The results of radiographical and histological assessments revealed that the cell transplant group had bone formations superior to those of the control group. Conclusions: This study suggests that peripheral blood MNCs have the potential to differentiate into osteoblasts. Although there are some hurdles in iPSC transplantation, osteoblasts obtained from MNC-iPSCs could be applied to bone regeneration therapy in the future.

Hueso: alteraciones relacionadas con obesidad / Bone: Obesity-Related Disorders

Resumen: El tejido óseo, anteriormente considerado como una estructura mecánica de soporte y movimiento, ha mostrado una participación importante en la homeostasis del organismo, incluyendo al metabolismo energético y el tejido adiposo. En la actualidad se considera un órgano endócrino que sintetiza moléculas reguladoras del metabolismo denominadas osteocinas. A su vez, el tejido adiposo, considerado como una glándula de secreción interna, ayuda a mantener la reserva energética del organismo y produce proteínas y moléculas como las adipocinas, algunas de las cuales afectan directamente al hueso. El análisis del ciclo resorción/formación ósea, muestra que la masa ósea es reflejo del balance entre ambas. Cuando se pierde este balance y hay reducción de la masa ósea con aumento de la fragilidad, aparece la osteoporosis lo que incrementa el riesgo de fractura. Una de cada 3 mujeres y 1 de cada 5 hombres mayores de 50 años presenta una fractura por osteoporosis. La interacción entre tejido adiposo y hueso está mediada por citocinas, osteocinas y adipocinas. La obesidad puede incidir en el hueso por varios mecanismos entre los cuales se encuentran los inflamatorios y los inducidos por citocinas derivadas de los adipocitos como la leptina y la adiponectina que pueden modificar el metabolismo óseo. Evidencias apoyan el efecto negativo de la obesidad sobre la salud del hueso, aunque estudios al respecto aún son contradictorios.

Abstract: The bone tissue, previously considered as a mechanical support for structure and movement, has shown an important participation in the homeostasis of the body, including energy metabolism and adipose tissue. Currently, it is considered an endocrine organ that synthesizes regulatory molecules of metabolism called osteokines. At the same time, the adipose tissue, considered as an internal secretion gland, helps to maintain the body energy and produces proteins and mol ecules such as adipokines, some of which affect the bone directly. The analysis of bone resorption/formation cycle shows that bone mass is a reflection of the balance between both. When this balance is lost and there is a reduction of bone mass with increased fragility, osteoporosis appears and increases the risk of fracture. One in three women and one in five men over 50 years old have a fracture due to osteoporosis. The interaction between adipose tissue and bone is mediated by cytokines, osteokines and adipokines. Obesity may affect the bone by several mechanisms, among which the inflammatory is included and those induced by cytokines secreted by adipocytes such as leptin and adiponectin which can modify bone metabolism. Evidence supports the negative effect of obesity on bone health, although studies about it are still contradictory.

Hops extract alleviates Aβ-injury to osteoblasts through antioxidant pathway / 药学实践杂志

Objective To explore the effects of Humulus lupulus L. extract (HLE) and its mechanism on improving bone formation of Aβ-injured osteoblasts. Methods Osteoblasts isolated from 24 h-old Wistar rats were injured by Aβ1-42 oligomer and intervened with HLE. The proliferation, differentiation and bone mineralization of osteoblasts were determined by MTT assay, alkaline phosphatase (ALP) activity assay and alizarin red staining, respectively. The apoptosis of osteoblasts was detected by flow cytometer. The expression levels of bone formation related proteins, and proteins of Nrf2 and FoxO1 pathways were measured by Western blotting analysis. The intranuclear expression of FoxO1 protein was detected by immunofluorescence. Results HLE significantly improved the cell proliferation, ALP activity and bone mineralization, and inhibited the apoptosis of Aβ-injured osteoblasts. HLE also significantly promoted the expressions of collagen type Ι (COL-I) and osteopontin (OPN) in Aβ-injured osteoblasts. HLE notably activated the Nrf2 and FoxO1 signaling pathways in Aβ-injured osteoblasts by promoting the expressions of related proteins and maintained bone metabolism through relieving oxidative stress. Conclusion This study confirms that HLE can alleviate Aβ-injury to osteoblasts, and preliminarily clarifies the mechanism being related to antioxidation, which provides a new reference for the mechanism research and drugs development for anti-osteoporosis.

Regulation of Osteoblasts and Osteoclasts by Secretory Factors Derived from Osteocytes under Mechanical Loading / 医用生物力学

Osteocytes are the main mechanical sensory and transductive cells of bone tissues. They connect with each other through many synaptic structures to form a huge regulatory network of bone steady-state cells, which are connected with osteoblasts, osteoclasts and other bone matrix surface cells. Osteocytes regulate bone metabolism and maintain bone regeneration by affecting osteoblast bone formation and osteoclast bone resorption through paracrine pathway. Aiming at the effects of some signal molecules or protein factors secreted or released by osteocytes after mechanical stimulation on the growth and differentiation of osteoblasts and osteoclasts, this paper reviews recent advances in how mechanically stimulated osteocytes communicate with osteoblasts and osteoclasts, so as to provide new ideas for the study of osteocytes biomechanics.

Osteogenic effects of antihypertensive drug benidipine on mouse MC3T3-E1 cells in vitro / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Hypertension is a prevalent systemic disease in the elderly, who can suffer from several pathological skeletal conditions simultaneously, including osteoporosis. Benidipine (BD), which is widely used to treat hypertension, has been proved to have a beneficial effect on bone metabolism. In order to confirm the osteogenic effects of BD, we investigated its osteogenic function using mouse MC3T3-E1 preosteoblast cells in vitro. The proliferative ability of MC3T3-E1 cells was significantly associated with the concentration of BD, as measured by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and cell cycle assay. With BD treatment, the osteogenic differentiation and maturation of MC3T3-E1 cells were increased, as established by the alkaline phosphatase (ALP) activity test, matrix mineralized nodules formation, osteogenic genetic test, and protein expression analyses. Moreover, our data showed that the BMP2/Smad pathway could be the partial mechanism for the promotion of osteogenesis by BD, while BD might suppress the possible function of osteoclasts through the OPG/RANKL/RANK (receptor activator of nuclear factor-κB (NF-κB)) pathway. The hypothesis that BD bears a considerable potential in further research on its dual therapeutic effect on hypertensive patients with poor skeletal conditions was proved within the limitations of the present study.