Downregulation of the LncRNA MEG3 Promotes Osteogenic Differentiation of BMSCs and Bone Repairing by Activating Wnt/β-Catenin Signaling Pathway

Background: Previous studies have demonstrated that long non-coding RNA maternally expressed gene 3 (MEG3) emerged as a key regulator in development and tumorigenesis. This study aims to investigate the function and mechanism of MEG3 in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and explores the use of MEG3 in skull defects bone repairing. Methods: Endogenous expression of MEG3 during BMSCs osteogenic differentiation was detected by quantitative real-time polymerase chain reaction (qPCR). MEG3 was knockdown in BMSCs by lentiviral transduction. The proliferation, osteogenic-related genes and proteins expression of MEG3 knockdown BMSCs were assessed by Cell Counting Kit-8 (CCK-8) assay, qPCR, alizarin red and alkaline phosphatase staining. Western blot was used to detect β-catenin expression in MEG3 knockdown BMSCs. Dickkopf 1 (DKK1) was used to block wnt/β-catenin pathway. The osteogenic-related genes and proteins expression of MEG3 knockdown BMSCs after wnt/β-catenin inhibition were assessed by qPCR, alizarin red and alkaline phosphatase staining. MEG3 knockdown BMSCs scaffold with PHMG were implanted in a critical-sized skull defects of rat model. Micro-computed tomography(micro-CT), hematoxylin and eosin staining and immunohistochemistry were performed to evaluate the bone repairing. Results: Endogenous expression of MEG3 was increased during osteogenic differentiation of BMSCs. Downregulation of MEG3 could promote osteogenic differentiation of BMSCs in vitro. Notably, a further mechanism study revealed that MEG3 knockdown could activate Wnt/β-catenin signaling pathway in BMSCs. Wnt/β-catenin inhibition would impair MEG3-induced osteogenic differentiation of BMSCs. By using poly (3-hydroxybutyrate-co-3-hydroxyhexanoate, PHBHHx)-mesoporous bioactive glass (PHMG) scaffold with MEG3 knockdown BMSCs, we found that downregulation of MEG3 in BMSCs could accelerate bone repairing in a critical-sized skull defects rat model. Conclusions: Our study reveals the important role of MEG3 during osteogenic differentiation and bone regeneration. Thus, MEG3 engineered BMSCs may be effective potential therapeutic targets for skull defects.

Immunocytochemical Labelling of Haematological Samples Using Monoclonal Antibodies

I reflect on my experience working with David Y. Mason in the Leukaemia Research Laboratories in the Nuffield Department of Pathology at the University of Oxford in the early 1980s. This was soon after the first monoclonal antibodies had been produced, which led to an exciting and productive time in biological discovery and pathology diagnostics. A specific focus in the laboratory was the development of immunoenzymatic staining methods that would enable monoclonal antibodies to be applied in diagnostic practice. This paper describes the work that led to the performance of immuno-alkaline phosphatase staining on blood and bone marrow smears, the success of which changed leukaemia diagnosis.

rBMSC osteogenic differentiation enhanced by graphene quantum dots loaded with immunomodulatory layered double hydroxide nanoparticles

Bone tissue defects caused by disease, trauma, aging or genetic factors emerged as one of the main factors that endanger human health. At present, advanced development of bone tissue engineering and regenerative medicine focused on the biomaterials regulated stem cell for responsive differentiation. In vivo transplantation of allogeneic bone materials has the needs of both osteogenic and immune regulation function. In this study, we utilized the extensively proved biocompatible layered double hydroxide (LDH) nanoparticles as the nanocarrier of graphene quantum dots (GQD), the functional loading was validated by characteristics analysis of scanning electron microscopy, surface zeta potential, X-ray diffraction and fourier transform infrared spectroscopy. Further, we investigated the cellular uptake of nanoparticles in rat bone marrow derived mesenchymal stem cells, the significant enhanced endocytosis was occurred in LDH-GQD treated groups. The enhanced osteogenic differentiation abilities of LDH-GQD were systematically investigated through alkaline phosphatase staining, alizarin red staining and qPCR analysis. In addition, the anti-inflammatory regulation of LDH facilitated the phenotypic transition of macrophage in LDH-GQD nanocomposites. Overall, the successful construction and functional validation of nanomaterials in this study will provide clinical therapeutic potential in bone defects regeneration.

Anti-Osteogenic Effect of Danshensu in Ankylosing Spondylitis: An in Vitro Study Based on Integrated Network Pharmacology

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized by abnormal bone metabolism, with few effective treatments available. Danshensu [3-(3,4-dihydroxy-phenyl) lactic acid) is a bioactive compound from traditional Chinese medicine with a variety of pharmacologic effects. In the present study, we investigated the pharmacologic effect and molecular mechanism of Danshensu in AS. Potential targets of Danshensu were identified in four drugs-genes databases; and potential pharmacologic target genes in AS were identified in three diseases-genes databases. Differentially expressed genes related to AS were obtained from the Gene Expression Omnibus database. Overlapping targets of Danshensu and AS were determined and a disease–active ingredient–target interaction network was constructed with Cytoscape software. Enrichment analyses of the common targets were performed using Bioconductor. To test the validity of the constructed network, an in vitro model was established by treating osteoblasts from newborn rats with low concentrations of tumor necrosis factor (TNF)-α. Then, the in vitro model and AS fibroblasts were treated with Danshensu (1–10 μM). Osteogenesis was evaluated by alkaline phosphatase staining and activity assay, alizarin red staining, quantitative PCR, and western blotting. We identified 2944 AS-related genes and 406 Danshensu targets, including 47 that were common to both datasets. The main signaling pathways associated with the targets were the c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) pathways. A low concentration of TNF-α (0.01 ng/ml) promoted the differentiation of osteoblasts; this was inhibited by Danshensu, which had the same effect on AS fibroblasts but had the opposite effect on normal osteoblasts. Danshensu also decreased the phosphorylation of JNK and ERK in AS fibroblasts. There results provide evidence that Danshensu exerts an anti-osteogenic effect via suppression of JNK and ERK signaling, highlighting its therapeutic potential for the treatment of AS.

Gujin Dan is A Chinese Medicine Formulation That Stimulates Cell Proliferation And Differentiation By Controlling Multiple Genes Involved In MC3T3-E1 Cells

Background: The development of Chinese medicine has been practised in China over a long period of time, and China has long used single medicines in various forms of decoction to treat illnesses, and later learned to combine several medicines to form formulas to enhance the effects of the medicines. The use of Chinese herbal medicines and formulas has played a pivotal role in the prevention and treatment of diseases in China since ancient times. The application of Chinese herbal preparations in the field of osteoporosis treatment has received widespread attention, and Gujin Dan（GJD） is one of the representative herbal formulas, however, the exact minute mechanism of its treatment of osteoporosis remains to be elucidated.Methods: In the study, we prepared an aqueous extract of GJD and measured the effect of different administration concentrations of GJD on cell proliferation by CCK-8 assay, and the effect of GJD on cell differentiation ability by Alizarin Red S Staining, Alkaline Phosphatase Staining and quantitative assay. Changes in gene expression patterns of MC3T3-E1 cells under GJD treatment were investigated by RNA-seq analysis and validation methods.Results: We demonstrate that GJD promotes the proliferation and differentiation of Mc3t3-e1 cells through the regulation of multiple functional genes. This was mainly achieved by regulating the expression levels of four categories of genes that promote the proliferation of Mc3t3-e1 cells or osteoblasts, inhibit apoptosis and autophagy, inhibit osteoclast formation and differentiation, and promote osteoblast differentiation. In addition, GJD slightly increased the expression levels of gene markers in osteoblasts. Conclusions: Our findings suggest that GJD promotes proliferation and differentiation of MC3T3-E1 cells and inhibits osteoclastogenesis and differentiation, as well as apoptosis and autophagy, through the synergistic interaction of various herbs and their active components in GJD. This study has significantly improved the current understanding of the molecular effects of GJD on MC3T3-E1 cells. This study also provides new ideas for possible strategies to further prevent and treat bone metabolism-related diseases using traditional Chinese medicinal preparations.

Cyclic Mechanical Strain Regulates Osteoblastic Differentiation of Mesenchymal Stem Cells on TiO2 Nanotubes Through GCN5 and Wnt/β-Catenin

Bone marrow mesenchymal stem cells (BMSCs) play a critical role in bone formation and are extremely sensitive to external mechanical stimuli. Mechanical signals can regulate the biological behavior of cells on the surface of titanium-related prostheses and inducing osteogenic differentiation of BMSCs, which provides the integration of host bone and prosthesis benefits. But the mechanism is still unclear. In this study, BMSCs planted on the surface of TiO2 nanotubes were subjected to cyclic mechanical stress, and the related mechanisms were explored. The results of alkaline phosphatase staining, real-time PCR, and Western blot showed that cyclic mechanical stress can regulate the expression level of osteogenic differentiation markers in BMSCs on the surface of TiO2 nanotubes through Wnt/β-catenin. As an important member of the histone acetyltransferase family, GCN5 exerted regulatory effects on receiving mechanical signals. The results of the ChIP assay indicated that GCN5 could activate the Wnt promoter region. Hence, we concluded that the osteogenic differentiation ability of BMSCs on the surface of TiO2 nanotubes was enhanced under the stimulation of cyclic mechanical stress, and GCN5 mediated this process through Wnt/β-catenin.

Effect of miR-192-5p on Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells in Idiopathic Scoliosis by Regulating Wnt/β-catenin Signaling Pathway via RSPO1

BackgroundIdiopathic scoliosis (IS) is the most common structural scoliosis, which seriously affects not only patient’s physical and mental health but also quality of patient’s life. Abnormal osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is one of the causes of IS. However, the regulation mechanism of osteogenic differentiation of BMSCs in patients with IS remains to be further studied.MethodsSerum samples of 135 patients with IS were collected, and the expression of miRNA were detected by RT-qPCR. BMSCs from patients with IS were collected and the expression of miR-192-5p in BMSCs from IS patients and normal BMSCs was detected by RT-qPCR. Double luciferase reporter genes assay was used to verify the targeting relationship between miR-192-5p and RSPO1. The levels of RSPO1, osteogenic related proteins (OC, OPN and RUNX2) and Wnt/β-catenin signaling pathway related proteins (WNT3A and β-catenin) were detected by Western blotting. Alkaline phosphatase staining and alizarin red staining were used to evaluate the osteogenesis of BMSCs.ResultsmiR-192-5p was significantly up-regulated in serum and BMSCs of patients with IS. Alkaline phosphatase staining and alizarin red staining showed that miR-192-5p inhibitor promoted the osteogenic differentiation of BMSCs from IS patients. miR-192-5p targeted down-regulated the expression of RSPO1 in BMSCs from IS patients. In addition, overexpression of RSPO1 activated Wnt/β-catenin signaling pathway in BMSCs from IS patients. Furthermore, miR-192-5p/RSPO1 axis regulated levels of osteogenic related proteins (OC, OPN and RUNX2) in BMSCs from IS patients through Wnt/β-catenin signaling pathway, and affected the osteogenic differentiation of BMSCs.ConclusionmiR-192-5p, which was highly expressed in patients with IS, inhibited Wnt/β-catenin signaling pathway by down-regulating RSPO1 protein and then reduced the osteogenic differentiation ability of BMSCs.

New Sintered Porous Scaffolds of Mg,Sr Co-Substituted Hydroxyapatite Support Growth and Differentiation of Primary Human Osteoblasts In Vitro

Strontium (Sr) and Magnesium (Mg) are bioactive ions that have been proven to exert a beneficial effect on bone; therefore, their incorporation into bone substitutes has long been viewed as a possible approach to improve tissue integration. However, the thermal instability of Mg-substituted hydroxyapatites has hitherto limited development. We previously described the creation of thermally consolidated porous constructs of Mg,Sr co-substituted apatites with adequate mechanical properties for their clinical use. The present paper describes the biocompatibility of Mg,Sr co-substituted granules using an alveolar-bone-derived primary model of human osteoblasts. Cells were cultured in the presence of different amounts of hydroxyapatite (HA), Sr-substituted HA, or MgSrHA porous macrogranules (with a size of 400–600 microns, obtained by grinding and sieving the sintered scaffolds) for three and seven days, and their viability was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Protein content was measured using the Lowry assay at the same time points. Cell viability was not impaired by any of the tested compounds. Indirect and direct biocompatibility of these macrogranules was assessed by culturing cells in a previously conditioned medium with HA, SrHA, or MgSrHA, or in the presence of material granules. Osteoblasts formed larger and more numerous nodules around SrHA or MgSrHA granules. Furthermore, cell differentiation was evaluated by alkaline phosphatase staining of primary cells cultured in the presence of HA, SrHA, or MgSrHA granules, confirming the increased osteoconductivity of the doped materials.

The role of quercetin in primary culture of ovine spermatogonial stem cells

The aim of the present study was to examine the effect of quercetin on the survival and primary culture of ovine spermatogonial stem cells (SSCs). The two-time enzymatic digestion process was employed to obtain SSCs from lamb testes. In the next step, the use of filtration and differential plating methods caused an increase in the number of SSCs in the cell suspension resulting from enzymatic and mechanical digestions. Mitomycin-C-treated Sertoli cells were used to prepare the feeder layer. The stem cells were then cultured on the Sertoli cell feeder layer. The identification of the colonies was done through alkaline phosphatase staining methods and specific gene expression of ram’s SSCs (nanog and Plzf). The results of methylthiazolyldiphenyl-tetrazolium bromide assay on SSCs 72 h after culture with different treatments of quercetin demonstrated that the highest percentage of survival was for 5 μM and 10 μM concentrations, respectively; however, compared to the control, no significant difference was observed. In comparison with the control, the concentration equal to and greater than 20 μM quercetin caused a significant decrease in the survival of SSCs (P < 0.05). Seven days after culture, 40 μM quercetin caused a substantial reduction in the mean number of colonies, compared to the control (P < 0.05). The results demonstrated that compared to the control, 5 μM to 40 μM of quercetin significantly reduced Plzf gene expression. Furthermore, the concentration equal to and higher than 10 μM quercetin significantly decreased bcl-2 gene expression in the cells under study (P < 0.05). Based on the findings of the present study, the use of quercetin for the primary culture of ovine SSCs is not recommended. It is suggested that the function of this antioxidant should be investigated on the differentiation of SSCs.

Revealing the influence of electron beam melted Ti-6Al-4V scaffolds on osteogenesis of human bone marrow-derived mesenchymal stromal cells

Porous Titanium-6Aluminum-4Vanadium scaffolds made by electron beam-based additive manufacturing (AM) have emerged as state-of-the-art implant devices. However, there is still limited knowledge on how they influence the osteogenic differentiation of bone marrow-derived mesenchymal stromal cells (BMSCs). In this study, BMSCs are cultured on such porous scaffolds to determine how the scaffolds influence the osteogenic differentiation of the cells. The scaffolds are biocompatible, as revealed by the increasing cell viability. Cells are evenly distributed on the scaffolds after 3 days of culturing followed by an increase in bone matrix development after 21 days of culturing. qPCR analysis provides insight into the cells’ osteogenic differentiation, where RUNX2 expression indicate the onset of differentiation towards osteoblasts. The COL1A1 expression suggests that the differentiated osteoblasts can produce the osteoid. Alkaline phosphatase staining indicates an onset of mineralization at day 7 in OM. The even deposits of calcium at day 21 further supports a successful bone mineralization. This work shines light on the interplay between AM Ti64 scaffolds and bone growth, which may ultimately lead to a new way of creating long lasting bone implants with fast recovery times.