Expression Of Osteogenic Markers Research Articles

Loss of signal transducer and activator of transcription 3 in osteoblasts impaired the bone healing in inflammatory microenvironment.

This study aimed to investigate the effect of Stat3 on the osteoblast-mediated bone healing in the inflammatory lesion. The conditional knockout of Stat3 in osteoblasts (Stat3 CKO) was generated via the Cre-loxP recombination system using Osterix-Cre transgenic mice. The calvarial bone inflammatory lesions were established on both Stat3 CKO and wild-type mice, then harvested to assess the bone healing. In response to lipopolysaccharide (LPS) stimulation, osteoblasts from Stat3 CKO and wild-type mice were subjected to examine the formation of calcium deposits, the expression of osteogenic markers (i.e., Runx2, OPN, COL1A1), and osteoclast-related markers (i.e., RANKL, OPG). The EdU and transwell assays were performed to assess the proliferation and migration of the cells. A decrease in bone mass and an increase in osteolysis were found in the inflammatory lesions on Stat3 CKO mice when compared with the control. More osteoclastic-like cells and an increased expression of RANKL were observed in Stat3 CKO mice. Both mRNA and protein expressions of Stat3 and osteogenic markers in the lesions were significantly decreased in Stat3 CKO mice. After co-cultured with osteogenic medium, the Stat3-deficient osteoblasts were found with a significant decrease in calcium deposits and the expression of osteogenic markers, and with a significant increased expression of RANKL. The impaired ossification of Stat3-deficient osteoblasts was even more pronounced with the presence of lipopolysaccharides in vitro. The most decrease in cell proliferation and migration was found in Stat3-deficient osteoblasts in response to LPS. Loss of Stat3 in osteoblasts impaired bone healing in an inflammatory microenvironment.

Roles of human periodontal ligament stem cells in osteogenesis and inflammation in periodontitis models: Effect of 1α,25-dihydroxyvitamin D3

Periodontitis is a chronic inflammatory disease caused by Porphyromonas gingivalis and other bacteria, and human periodontal ligament stem cells (hPDLSCs) are a promising candidate for the treatment of periodontal supporting tissue defects. This study aimed to investigate the effect of 1α,25-dihydroxyvitamin D3 [1,25(OH)2VitD3] on osteogenic differentiation of hPDLSCs in an in vitro periodontitis model and whether it can improve inflammatory status. hPDLSCs were in vitro isolated and identified. After treatment with 1,25(OH)2VitD3 and ultrapure pure Porphyromonas gingivalis lipopolysaccharide (LPS-G), the viability of hPDLSCs was detected using Cell Counting Kit-8, the expressions of osteogenic markers and inflammatory genes using Western blotting and quantitative reverse transcription PCR (qRT-PCR), the levels of inflammatory factors in cells using enzyme linked immunosorbent assay (ELISA), and the fluorescence signal intensity of osteoblastic markers and inflammatory genes in cells using immunofluorescence assay. It was found that 1,25(OH)2VitD3 reversed the inhibition of hPDLSCs proliferation by LPS-G; LPS-G exhibited inhibitory effect on ALP, Runx2, and OPN expressions, and such inhibitory effect was significantly weakened when co-acting with 1,25(OH)2VitD3. Meanwhile, LPS-G upregulated the expressions of inflammatory genes IL-1β and Casp1, whereas 1,25(OH)2VitD3 antagonized such an effect and improved the inflammatory status. In conclusion, 1,25(OH)2VitD3 can reverse the inhibitory effect of LPS-G on hPDLSCs proliferation and osteogenic differentiation and suppress LPS-G-induced upregulation of inflammatory gene expressions.

A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo.

Introduction: Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur. Methods: Embryonic mesenchymal stem cells were cultured on RP and SSM scaffolds for 7d under perfusion to create Si-CAOP grafts with terminally differentiated osteoblasts and mineralizing bone matrix. These scaffolds were implanted into the segmental defects in combination with an arteriovenous bundle (AVB). Native scaffolds without cells or AVB served as controls. After 3 and 6months, femurs were processed for angio-µCT or hard tissue histology, histomorphometric and immunohistochemical analysis of angiogenic and osteogenic marker expression. Results: At 3 and 6months, defects reconstructed with RP scaffolds, cells and AVB displayed a statistically significant higher bone area fraction, blood vessel volume%, blood vessel surface/volume, blood vessel thickness, density and linear density than defects treated with the other scaffold configurations. Discussion: Taken together, this study demonstrated that the AVB technique is well suited for inducing adequate vascularization of the tissue engineered scaffold graft in segmental defects after 3 and 6months, and that our tissue engineering approach employing 3D powder bed printed scaffolds facilitated segmental defect repair.

#3048 INDOXYL SULFATE INHIBITS OSTEOGENESIS OF BONE MARROW DERIVED MESENCHYMAL STEM CELLS THROUGH AHR/HES1/BMP2 PATHWAY

Abstract Background and Aims There is a high global burden of chronic kidney disease (CKD). The increased risk of bone fracture in patients with CKD suggests that CKD-associated factors, such as uremic toxins, might be the cause. Recent studies demonstrated that low turnover osteodystrophy and bone formation defect develop in early CKD, which indicates that uremic toxins, particularly in relatively low concentrations, can potentially be a cause. Thus far, studies about defected osteogenesis adopted high concentrations of uremic toxins (for example, indoxyl sulfate (ISx) >100 μM). Furthermore, the pathology is not yet fully investigated. Uremic toxin induced aryl hydrocarbon receptor (AHR) has been linked to bone formation defect, however, the mechanisms are incompletely understood. AHR inhibit osteogenesis during early processes of differentiation of early cells (stem cells), but whether uremic toxins induced AHR to affect stem cell in osteogenesis lineage has yet to be studied. The present study aims to clarify whether ISx at concentrations approximate to average in CKD patients (20 μM in free form) affect osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs), and further survey the underline signal transduction of AHR-induced defected osteogenesis. Method Mineralization of D1 cells (mouse BMSCs) was evaluated by alizarin red S staining (ARS). The mRNA expressions and protein levels of osteogenic markers including Runx2, BMP2, ALP, and osteocalcin were determined by quantitative real-time polymerase chain reaction (RT-PCR) and western blotting. AHR translocation into the nucleus was evaluated by an immunofluorescence confocal microscope. Reporter gene assays were adopted to study the transcriptional regulation of Runx2 and BMP2. Results ISx at concentrations ≤50 μM significantly downregulated mineralization of BMSCs with the most influence in the early stage of osteogenesis. ISx decreased the mRNA expressions and protein levels of osteogenic markers Runx2, BMP2, ALP, and osteocalcin. ISx of 50 μM induced AHR translocation into the nucleus and upregulated AHR target genes CYP1a1 and CYP1b1. The ISx-induced mineralization defects of BMSCs were counteracted by AHR antagonist CH223191, while downregulated gene expressions of osteogenic markers were recovered by AHR antagonist and knockdown (KD) of AHR. In mechanistic studies, ISx upregulated mRNA levels of hairy and enhancer of split (HES1), which is a primary target of NOTCH signaling. Although there were no significant differences in expressions of Notch1∼4, the upregulated Hes1 was attenuated by the antagonist and KD of AHR, which indicated that Hes1 was directly regulated by AHR. We identified putative binding sites of transcription repressor Hes1 in the promoter area of BMP2 and Runx2. Following experimental treatment of ISx, expression levels of BMP2 and Runx2 monitored by reporter assays were downregulated, which indicated that Hes1 plays as a transcription repressor to downregulated BMP2 and Runx2. Conclusion ISx under clinically relevant concentrations attenuated mineralization of BMSCs, particularly in the early stage of osteogenesis. ISx-induced AHR upregulated Hes1, which inhibited expressions of not only Runx2, but also BMP2, which has not been published before. A study of the underline signal transduction pathways relevant to the AHR genomic control system may provide potential therapy for low bone formation in early CKD.

Dissecting specific Wnt components governing osteogenic differentiation potential by human periodontal ligament stem cells through interleukin-6

Periodontal ligament stem cells (PDLSCs) play a significant role on periodontal tissue and alveolar bone homeostasis. During inflammation, interleukin (IL)-6 serves as one of key cytokine players controlling tissue reaction as well as alveolar bone tissue remodeling. It is believed that periodontal tissue inflammation causes periodontium degradation, especially alveolar bone. However, in this study, we show that an inflammatory mediator, IL-6, may serve another direction on alveolar bone homeostasis during inflammatory condition. We found that, IL-6 at 10 and 20 ng/mL was not cytotoxic and dose-dependently exerted beneficial effects on osteogenic differentiation of human PDLSCs (hPDLSCs), as demonstrated by increased alkaline phosphatase activity, mRNA expression of osteogenic markers, and matrix mineralization. The presence of physiological and inflammatory level of IL-6, the osteogenic differentiation potential by hPDLSCs was enhanced by several possible mechanisms including transforming growth factor (TGF), Wnt, and Notch pathways. After in-depth and thorough exploration, we found that Wnt pathway serves as key regulator controlling osteogenic differentiation by hPDLSCs amid the IL-6 presentation. Surprisingly, apart from other mesenchymal stem cells, distinct Wnt components are employed by hPDLSCs, and both canonical and non-canonical Wnt pathways are triggered by different mechanisms. Further validation by gene silencing, treatment with recombinant Wnt ligands, and β-catenin stabilization/translocation confirmed that IL-6 governed the canonical Wnt/β-catenin pathway via either WNT2B or WNT10B and employed WNT5A to activate the non-canonical Wnt pathway. These findings fulfill the homeostasis pathway governing periodontal tissue and alveolar bone regeneration and may serve for further therapeutic regimen design for restoring the tissues.

The prophylactic effects of naringin on steroid-induced early-stage osteonecrosis in rats: a preliminary study.

The excessive steroid may cause dyslipidaemia and oxidative insult during femoral head osteonecrosis, inducing bone loss and impairment of the intraosseous blood system. In contrast, bio-flavanone naringin has shown antioxidant, antiresorptive and lipid-lowering bioactivities. The present research is an effort to explore the anti-ON potential of naringin in vivo and in vitro. After a 6-week treatment, the femora were dissected for histological examination following bone mineral density assay by X-ray absorptiometry. Blood samples were examined for coagulation, oxidative stress, lipid transportation and endothelial injury. Marrow samples were cultured and assayed for adipogenic and osteogenic alterations by ALP activity, mineralization, RT-qPCR and western blot analysis. The results showed that naringin exerted a dose-dependent effect on reducing ON incidence, with inhibition of osteoporosis, oxidative stress and dyslipidaemia. The mechanism included the suppression of PPARγ2 for adipogenesis of bone marrow stem cells (BMSCs) and the prevention of oxidative stress in endothelium injury. Naringin may restore steroid-impaired osteogenesis by enhancing the mRNA and protein expression of osteogenic markers in a dose-ascending manner and new bone formation can be found in naringin groups. Taken together, our findings showed that naringin may serve as a prophylactic agent and selective PPARγ modulator for the early-stage ON.

Mesoporous Core-Cone Silica Nanoparticles Can Deliver miRNA-26a to Macrophages to Exert Immunomodulatory Effects on Osteogenesis In Vitro.

Nanoparticles can play valuable roles in delivering nucleic acids, including microRNAs (miRNA), which are small, non-coding RNA segments. In this way, nanoparticles may exert post-transcriptional regulatory influences on various inflammatory conditions and bone disorders. This study used biocompatible, core-cone-structured, mesoporous silica nanoparticles (MSN-CC) to deliver miRNA-26a to macrophages in order to influence osteogenesis in vitro. The loaded nanoparticles (MSN-CC-miRNA-26) showed low-level toxicity towards macrophages (RAW 264.7 cells) and were internalized efficiently, causing the reduced expression of pro-inflammatory cytokines, as seen via real-time PCR and cytokine immunoassays. The conditioned macrophages created a favorable osteoimmune environment for MC3T3-E1 preosteoblasts, driving osteogenic differentiation with enhanced osteogenic marker expression, alkaline phosphatase (ALP) production, extracellular matrix formation, and calcium deposition. An indirect co-culture system revealed that direct osteogenic induction and immunomodulation by MSN-CC-miRNA-26a synergistically increased bone production due to the crosstalk between MSN-CC-miRNA-26a-conditioned macrophages and MSN-CC-miRNA-26a-treated preosteoblasts. These findings demonstrate the value of nanoparticle delivery of miR-NA-26a using MSN-CC for suppressing the production of pro-inflammatory cytokines with macrophages and for driving osteogenic differentiation in preosteoblasts via osteoimmune modulation.

Axin2-CreERT2 mediated knockout of bone morphogenetic protein receptor type 1A caused abnormal secondary dentine and altered cell fate of Axin2-expressing odontogenic cells.

Inducing odontogenic differentiation and tubular dentine formation is extremely important in dentine repair and tooth regeneration. Bone morphogenic proteins (BMPs) signalling plays a critical role in dentine development and tertiary dentine formation, whilst how BMPR1A-mediated signalling affects odontoblastic differentiation of Axin2-expressing (Axin2+ ) odontogenic cells and tubular dentine formation remains largely unknown. This study aims to reveal the cellular and molecular mechanisms involved in the formation of secondary dentine. Axin2lacZ/+ mice harvested at post-natal 21 (P21) were used to map Axin2+ mesenchymal cells. Axin2CreERT2/+ ; R26RtdTomato/+ mice and Axin2CreERT2/+ ; R26RDTA/+ ; R26RtdTomato/+ mice were generated to observe the tempo-spatial distribution pattern of Axin2-lineage cells and the effect of ablation of Axin2+ cells on dentinogenesis, respectively. A loss-of-function model was established with Axin2CreERT2/+ ; Bmpr1afl/fl ; R26RtdTomato/+ (cKO) mice to study the role of BMP signalling in regulating Axin2+ cells. Micro-computed tomography, histologic and immunostainings, and other approaches were used to examine biological functions, including dentine formation, mineralization and cell differentiation in cKO mice. The results showed rich expression of Axin2 in odontoblasts at P21. Lineage tracing assay confirmed the wide distribution of Axin2 lineage cells in odontoblast layer and dental pulp during secondary dentine formation (P23 to P56), suggesting that Axin2+ cells are important cell source of primary odontoblasts. Ablation of Axin2+ cells (DTA mice) significantly impaired secondary dentine formation characterized with notably reduced dentine thickness (Mean of control: 54.11 μm, Mean of DTA: 27.79 μm, p = .0101). Furthermore, malformed osteo-dentine replaced the tubular secondary dentine in the absence of Bmpr1a with irregular cell morphology, abnormal cellular process formation and lack of cell-cell tight conjunction. Remarkably increased expression of osteogenic markers like Runx2 and DMP1 was detected, whilst DSP expression was observed in a dispersed manner, indicating an impaired odontogenic cell fate and failure in producing tubular dentine in cKO mice. Axin2+ cells are a critical population of primary odontoblasts which contribute to tubular secondary dentine formation, and BMP signalling pathway plays a vital role in maintaining the odontogenic fate of Axin2+ cells.

The Self-assembling peptide P11-4 influences viability and osteogenic differentiation of stem cells of the apical papilla (SCAP)

ObjectiveTo analyze the effect of P11–4 self-assembly peptide on cell viability and osteogenic capacity of SCAPs through mineral deposition and gene expression of osteogenic markers. MethodsSCAPs were seeded in contact with P11–4 (10 µg/ml, 100 µg/ml and 1 mg/ml) solution. Cell viability was evaluated using a colorimetric assay MTT: 3-(4,5-dimethyl-thiazolyl-2)-2,5- diphenyltetrazolium bromide) in an experimental time of 24, 48 and 72 h (n = 7). Mineral deposition and quantification provided by the cells was tested using the Alizarin Red staining and Cetylpyridinium Chloride (CPC), respectively, after 30 days (n = 4). Gene expression of Runt-related transcription factor 2 (RUNX2), Alkaline phosphatase (ALP) and Osteocalcin (OCN) was quantified using quantitative polymerase chain reaction (RT-qPCR), at 3 and 7 days with Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the housekeeping gene, and relative gene expression was measured using the ΔΔCq method. Data were analyzed using Kruskall-Wallis followed by multiple comparisons, and T-test for gene expression with α=0.05. ResultsAll tested concentrations (10 µg/ml, 100 µg/ml and 1 mg/ml) were not cytotoxic at time 24 and 48 h. After 72 h, a slight decrease in cell viability was observed for the lowest concentration (10 µg/ml). The concentration of 100 µg/ml P11–4 showed the highest mineral deposition. However, qPCR analysis of P11–4 (10 µg/ml) showed upregulation of RUNX2 and OCN at 3 days, with downregulation of ALP at 3 and 7d ConclusionP11–4 did not affect cell viability, induced mineral deposition in SCAPs, and upregulated the expression of RUNX2 and OCN genes at 3 days, while downregulating ALP expression at 3 and 7 days. Clinical significanceBased on the results obtained in this study it can be stated that self-assembling peptide P11–4 is a potential candidate to induce mineralization on dental stem cells for regenerative purposes and also for a clinical use as a capping agent without compromising the cells health.

Cellular Response to Bone Morphogenetic Proteins-2 and -7 Covalently Bound to Photocrosslinked Heparin-Diazoresin Multilayer.

Despite the plethora of research that exists on recombinant human bone morphogenetic protein-2 and -7 (rhBMP-2 and rhBMP-7) and has been clinically approved, there is still a need to gain information that would allow for their more rational use in bone implantology. The clinical application of supra-physiological dosages of these superactive molecules causes many serious adverse effects. At the cellular level, they play a role in osteogenesis and cellular adhesion, migration, and proliferation around the implant. Therefore, in this work, we investigated the role of the covalent binding of rhBMP-2 and rhBMP-7 separately and in combination with ultrathin multilayers composed of heparin and diazoresin in stem cells. In the first step, we optimized the protein deposition conditions via quartz crystal microbalance (QCM). Then, atomic force microscopy (AFM) and enzyme-linked immunosorbent assay (ELISA) were used to analyze protein-substrate interactions. The effect of the protein binding on the initial cell adhesion, migration, and short-term expression of osteogenesis markers was tested. In the presence of both proteins, cell flattening and adhesion became more prominent, resulting in limited motility. However, the early osteogenic marker expression significantly increased compared to the single protein systems. The presence of single proteins resulted in the elongation of cells, which promoted their migration activity.

Human Ovarian Follicular Fluid Mesenchymal Stem Cells Express Osteogenic Markers When Cultured on Bioglass 58S-Coated Titanium Scaffolds.

Recent studies have reported that stem cells (human follicular fluid mesenchymal stem cells or hFF-MSCs) are present in ovarian follicular fluid (hFF) and that they have a proliferative and differentiative potential which is similar to that of MSCs derived from other adult tissue. These mesenchymal stem cells, isolated from human follicular fluid waste matter discarded after retrieval of oocytes during the IVF process, constitute another, as yet unutilized, source of stem cell materials. There has been little work on the compatibility of these hFF-MSCs with scaffolds useful for bone tissue engineering applications and the aim of this study was to evaluate the osteogenic capacity of hFF-MSCs seeded on bioglass 58S-coated titanium and to provide an assessment of their suitability for bone tissue engineering purposes. Following a chemical and morphological characterization with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), cell viability, morphology and expression of specific osteogenic markers were examined after 7 and 21 days of culture. The hFF-MSCs seeded on bioglass and cultured with osteogenic factors, when compared with those seeded on tissue culture plate or on uncoated titanium, exhibited enhanced cell viability and osteogenic differentiation, as reflected by increased calcium deposition and increased ALP activity with expression and production of bone-related proteins. Taken together, these results demonstrate that MSCs from human follicular fluid waste materials can be easily cultured in titanium scaffolds coated with bioglass, having osteoinductive properties. This process has significant potential for regenerative medicine applications and indicates that hFF-MSCs may be a valid alternative to hBM-MSC cells in experimental models in bone tissue engineering.

Osteogenic Potential and Bioactive Profiles of Piper sarmentosum Ethanolic Extract-Treated Stem Cells.

Piper sarmentosum is a well-known traditional herbal plant in various diseases treatments. Multiple scientific studies have also reported various biological activities exhibited by the plant's extract, such as antimicrobial, anticarcinogenic and antihyperglycemic activities, and, in addition, a bone protective effect in ovariectomized rats has been reported. However, no known Piper sarmentosum extract is involved in osteoblast differentiation using stem cells. Our study aims to identify the potential of P. sarmentosum ethanolic extract to induce osteoblast differentiation of human peripheral blood stem cells. Prior to the assay, the proliferation ability of the cells was observed for 14 days and the presence of hematopoietic stem cells in the culture was determined by the expression of SLAMF1 and CD34 genes. During the differentiation assay, the cells were treated with P. sarmentosum ethanolic extract for 14 days. Osteoblast differentiation was examined using an (alkaline phosphatase) ALP assay, by monitoring the expression of osteogenic gene markers and by von Kossa staining. The untreated cells served as the negative control, while cells treated with 50 µg/mL ascorbic acid and 10 mM β-glycerophosphate acted as the positive control. Finally, the determination of the compound profile was performed using a gas chromatography-mass spectrometry (GC-MS) analysis. The isolated cells were able to proliferate for 14 days during the proliferation assay. The expression of hematopoietic stem cell markers was also upregulated during the 14 days assay. Following the differentiation induction, the ALP activity exhibited a significant increase (p < 0.05) from day 3 of the differentiation assay. A molecular analysis also showed that the osteogenic markers ALP, RUNX2, OPN and OCN were upregulated compared to the positive control. The presence of mineralized cells with a brownish-stained morphology was observed, indicating the mineralization process increased in a time-dependent manner regardless of the concentration used. There were 54 compounds observed in the GC-MS analysis, including β-asarones, carvacrol and phytol, which have been shown to possess osteoinductive capacities. Our results demonstrate that the ethanolic extract of P. sarmentosum can induce osteoblast differentiation of peripheral blood stem cells. The extract contains potent compounds which can potentially induce the differentiation of bone cells, i.e., osteoblasts.

The effect of epigenetic reprogramming using MI192 HDAC inhibitor on enhancing the osteogenesis of human adipose-derived stem cells in vitro.

The ability to control stem cell function is the key to stem cell-based therapy and living tissue regeneration. In natural conditions, histone deacetylases (HDAC) are regarded as the important defining epigenetic reprogramming for stem cell differentiation. To date, human adipose-derived stem cells (hADSCs) have been widely utilised for bone tissue engineering applications. The present study aimed to examine the effect of a novel HDAC2&3-selective inhibitor, MI192, on hADSCs epigenetic reprogramming for regulating its osteogenic potential in vitro. The results confirmed that MI192 treatment reduced the hADSCs viability in a time and dose-dependent manner. The optimal concentration and pre-treatment time of MI192 for hADSCs osteogenic induction was 30 μM and 2 days representatively. A quantitative biochemical assay confirmed that the pre-treatment with MI192 (30 μM) for 2 days significantly enhanced hADSCs alkaline phosphatase (ALP) specific activity (P<0.05) compared with that of the valproic acid (VPA) pre-treatment group. Real-time PCR analysis revealed that MI192 pre-treatment up-regulated hADSCs gene expressions of osteogenic markers (e.g., Runx2, Col1, and OCN) under the osteogenic induction. DNA flow cytometric analysis indicated that two days' pre-treatment with MI192 (30 μM) resulted in G2/M arrest in hADSCs and this G2/M arrest was reversible. Our results suggest that MI192 is capable of epigenetic reprogramming of hADSCs via HDAC inhibition for controlling the cell cycle, resulting in enhancing hADSCs osteogenic differentiation, which indicates the potential of using MI192 for promoting bone tissue regeneration.

Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum

Ectopic osteogenesis refers to the occurrence of osteoblasts in soft tissues other than bone tissue and the formation of bone tissue. The ligamentum flavum is an essential connecting structure between adjacent vertebral lamina, which participates in the formation of the vertebral canal's posterior wall and maintains the vertebral body's stability. Ossification of the ligamentum flavum (OLF) is one of the manifestations of systemic ossification of the spinal ligaments and one of the degenerative diseases related to the spine. However, there is a lack of research on the expression and biological function of Piezo1 in ligamentum flavum. Whether Piezo1 participates in the development of OLF is still unclear. The FX-5000C cell or tissue pressure culture and real-time observation and analysis system was applied to stretch ligamentum flavum cells to detect the expression of mechanical stress channel and osteogenic markers after the effect of different stretching durations. The results showed elevated expression of mechanical stress channel Piezo1 and osteogenic markers with the effect of tensile time duration. In conclusion, Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum. An approved explanatory model and further research will be required in the future.

The Effect of Sclerostin and Monoclonal Sclerostin Antibody Romosozumab on Osteogenesis and Osteoclastogenesis Mediated by Periodontal Ligament Fibroblasts.

Sclerostin is a bone formation inhibitor produced by osteocytes. Although sclerostin is mainly expressed in osteocytes, it was also reported in periodontal ligament (PDL) fibroblasts, which are cells that play a role in both osteogenesis and osteoclastogenesis. Here, we assess the role of sclerostin and its clinically used inhibitor, romosozumab, in both processes. For osteogenesis assays, human PDL fibroblasts were cultured under control or mineralizing conditions with increasing concentrations of sclerostin or romosozumab. For analyzing osteogenic capacity and alkaline phosphatase (ALP) activity, alizarin red staining for mineral deposition and qPCR of osteogenic markers were performed. Osteoclast formation was investigated in the presence of sclerostin or romosozumab and, in PDLs, in the presence of fibroblasts co-cultured with peripheral blood mononuclear cells (PBMCs). PDL-PBMC co-cultures stimulated with sclerostin did not affect osteoclast formation. In contrast, the addition of romosozumab slightly reduced the osteoclast formation in PDL-PBMC co-cultures at high concentrations. Neither sclerostin nor romosozumab affected the osteogenic capacity of PDL fibroblasts. qPCR analysis showed that the mineralization medium upregulated the relative expression of osteogenic markers, but this expression was barely affected when romosozumab was added to the cultures. In order to account for the limited effects of sclerostin or romosozumab, we finally compared the expression of SOST and its receptors LRP-4, -5, and -6 to the expression in osteocyte rich-bone. The expression of SOST, LRP-4, and LRP-5 was higher in osteocytes compared to in PDL cells. The limited interaction of sclerostin or romosozumab with PDL fibroblasts may relate to the primary biological function of the periodontal ligament: to primarily resist bone formation and bone degradation to the benefit of an intact ligament that is indented by every chew movement.

Wrinkled topography regulates osteogenesis via autophagy-mediated Wnt/β-catenin signaling pathway in MC3T3-E1 cells

ObjectiveIn this study, we aimed to evaluate the effects of different dimensional wrinkled in topography on the osteogenic differentiation of MC3T3-E1 cells and explored the underlying mechanisms. DesignPolydimethylsiloxane (PDMS) with a wrinkled topography was synthesized using an elastomer base and crosslinking while observing by atomic force microscopy. MC3T3-E1 proliferation was detected by Cell Counting Kit-8(CCK-8) assays and the cell morphology was determined by phalloidin staining. Osteogenetic genes expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. In addition, Autophagy-related genes expression levels were evaluated by immunostaining and western blotting in MC3T3-E1 in order to assess the induction of autophagy. ResultsIn this experiment, the 0.7 µm amplitude and 3 µm wavelength (W3) group increased the expression of osteogenic markers, whereas the 4.3 µm amplitude and 27 µm wavelength (W27) group showed inhibition. Both the cytoplasm and the nucleus of β-catenin, compared with those of the Flat, W3 increased, whereas W27 decreased. At the same time, the autophagy was consistent with the influence of the topography on osteogenic differentiation. Moreover, using CQ or RAPA significantly inhibited or promoted autophagy, as well as partially decreasing or increasing osteogenesis, respectively. Infecting siRNA-β-catenin decreased the expression of RUNX2 and OSX in MC3T3-E1 cells both treated with CQ and RAPA. ConclusionsWrinkled topographies activated the autophagy-mediated Wnt/β-catenin signaling pathway and affected the osteogenic differentiation of MC3T3-E1 cells. The introduction of aligned topographies on biomaterial scaffolds could provide physical cues with which modulate MC3T3-E1 responses for bone engineering constructs.

TGF-BETA STIMULATES PERIOSTEAL OSTEOGENIC ACTIVITY

Osteoprogenitors on the inner layer of periosteum are the major cellular contributors to appositional bone growth and bone repair by callus formation. Previous work showed that periosteal-derived cells have little or no osteogenic activity under standard in vitro osteogenic culture conditions. This study was conducted to determine what growth factor(s) can activate periosteal osteogenic capacity.This study was conducted with IACUC approval. Periosteum from five equine donors was digested in collagenase for 3-4 hours at 37C. Isolated periosteal cells were maintained in DMEM/10% FBS medium and exposed to PDGF, Prostaglandin E2, BMP-2 and TGF-b3 at a range of concentrations for 72 hours. Changes in osteogenic gene expression (Runx2, OSX and ALP) were measured by qPCR. Periosteal cells were pre-treated with TGF-b3 or maintained in control medium were transferred into basal or osteogenic medium. Osteogenic status was assessed by Alizarin Red staining for mineralized matrix, ALP enzymatic activity and induction of osteogenic genes.PDGF, PgE2 and BMP-2 had little impact on expression of osteogenic markers by periosteal cells. In contrast, TGF-b3 stimulated significant increases in Osterix (over 100-fold) ALP expression (over 70-fold). Pre-treating periosteal cells with TGF-b3 for 72 hours stimulated rapid cell aggregation and aggregate mineralization once cells were transferred to osteogenic medium, while cells not exposed to TGF-b3 exhibited minimal evidence of osteogenic activity.This study indicate that TGF-b signaling is vital for periosteal osteogenic activity. Transient ‘priming’ of periosteal cells through TGF-b exposure was sufficient to activate subsequent osteogenesis without requiring ongoing growth factor stimulation. TGF beta ligands are secreted by many cell types, including periosteal progenitors and osteocytes, providing opportunities for both autocrine and paracrine pathways to regulate periosteal bone formation under homeostatic and reparative conditions.

Spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells maintain pluripotency of stem cells by regulating hypoxia-inducible factors

BackgroundSpontaneous spheroid culture is a novel three-dimensional (3D) culture strategy for the rapid and efficient selection of progenitor cells. The objectives of this study are to investigate the pluripotency and differentiation capability of spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells (AB-MSCs); compare the advantages of spontaneous spheroids to those of mechanical spheroids; and explore the mechanisms of stemness enhancement during spheroid formation from two-dimensional (2D) cultured cells.MethodsAB-MSCs were isolated from the alveolar bones of C57BL/6 J mice. Spontaneous spheroids formed in low-adherence specific culture plates. The stemness, proliferation, and multi-differentiation capacities of spheroids and monolayer cultures were investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, alkaline phosphatase (ALP) activity, and oil-red O staining. The pluripotency difference between the spontaneous and mechanical spheroids was analyzed using RT-qPCR. Hypoxia-inducible factor (HIFs) inhibition experiments were performed to explore the mechanisms of stemness maintenance in AB-MSC spheroids.ResultsAB-MSCs successfully formed spontaneous spheroids after 24 h. AB-MSC spheroids were positive for MSC markers and pluripotency markers (Oct4, KLF4, Sox2, and cMyc). Spheroids showed higher Ki67 expression and lower Caspase3 expression at 24 h. Under the corresponding conditions, the spheroids were successfully differentiated into osteogenic and adipogenic lineages. AB-MSC spheroids can induce neural-like cells after neurogenic differentiation. Higher expression of osteogenic markers, adipogenic markers, and neurogenic markers (NF-M, NeuN, and GFAP) was found in spheroids than in the monolayer. Spontaneous spheroids exhibited higher stemness than mechanical spheroids did. HIF-1α and HIF-2α were remarkably upregulated in spheroids. After HIF-1/2α-specific inhibition, spheroid formation was significantly reduced. Moreover, the expression of the pluripotency genes was suppressed.ConclusionsSpontaneous spheroids from AB-MSCs enhance stemness and pluripotency. HIF-1/2α plays an important role in the stemness regulation of spheroids. AB-MSC spheroids exhibit excellent multi-differentiation capability, which may be a potent therapy for craniomaxillofacial tissue regeneration.

BMP9‐induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/β‐catenin signalling

Journal of Cellular and Molecular MedicineVolume 27, Issue 8 p. 1155-1156 CORRIGENDUMOpen Access BMP9-induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/β-catenin signalling This article corrects the following: BMP-9-induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/β-catenin signalling Ni Tang, Wen-Xin Song, Jinyong Luo, Xiaoji Luo, Jin Chen, Katie A. Sharff, Yang Bi, Bai-Cheng He, Jia-Yi Huang, Gao-Hui Zhu, Yu-Xi Su, Wei Jiang, Min Tang, Yun He, Yi Wang, Liang Chen, Guo-Wei Zuo, Jikun Shen, Xiaochuan Pan, Russell R. Reid, Hue H. Luu, Rex C. Haydon, Tong-Chuan He, Volume 13Issue 8bJournal of Cellular and Molecular Medicine pages: 2448-2464 First Published online: November 3, 2008 First published: 12 April 2023 https://doi.org/10.1111/jcmm.17715AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL In Tang et al.,1 the image for ‘BMP9+GFP Day 14’ was mistakenly duplicated with a higher magnification version of the image from ‘BMP9+FrzB Day 14’ in Figure 5E. The corrected figure is shown below. The authors confirm all results and conclusions of this article remain unchanged. FIGURE 5Open in figure viewerPowerPoint β-Catenin also plays an important role in BMP-9-induced late stage of osteogenic differentiation. (A) Synergistic effect between β-catenin and BMP-9 on osteocalcin promoter reporter. C3H10T1/2 cells were transfected with p6OSE2-Luc reporter and infected with varying titres of Adβ-Cat*, in the presence or absence of BMP-9 conditioned medium. At 48 h, cells were collected for luciferase assay. Data are present as mean ± SD. (B) Synergistic effect between β-catenin and Runx2 on osteocalcin promoter reporter. C3H10T1/2 cells were transfected with p6OSE2-Luc reporter and co-infected with varying titres of Adβ-Cat* and/or AdRunx2. At 48 h, cells were collected for luciferase assay. Data are present as mean ± SD. (C) Knockdown of β-catenin inhibits BMP-9-induced activation of osteocalcin promoter reporter. C3H10T1/2 cells were transfected with p6OSE2-Luc and infected with varying titres of AdR-simBC in the presence of BMP-9 conditioned medium. Cells were collected for luciferase at the indicated time-points. (D) Knockdown of β-catenin inhibits BMP-9-induced expression of late osteogenic markers. C3H10T1/2 cells were co-infected with AdBMP-9 and AdR-simBC or AdGFP for 10 days. Total RNA was isolated for RT-PCR and qPCR analysis using primers specific for mouse osteocalcin and osteopontin. Experiments were done in triplicate. (E) Silencing of β-catenin and FrzB overexpression inhibit BMP-9-induced mineralization. C3H10T1/2 cells were co-infected with AdBMP-9 and AdFrzB, AdR-simBC, or AdGFP. At 14 and 21 days after infection, cells were fixed and subjected to Alizarin Red S staining. Representative images are shown (magnification, 40×). REFERENCE 1Tang N, Song W-X, Luo J, et al. BMP-9-induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/beta-catenin signalling. J Cell Mol Med. 2009; 13(8B): 2448- 2464. doi:10.1111/j.1582-4934.2008.00569.x Volume27, Issue8April 2023Pages 1155-1156 FiguresReferencesRelatedInformation

Liraglutide in Combination with Insulin Has a Superior Therapeutic Effect to Either Alone on Fracture Healing in Diabetic Rats.

Fractures in patients with type 2 diabetes mellitus are at a high risk of delayed union or non-union. Previous studies have shown a protective effect of liraglutide on bone. In the present study, we aimed to investigate the effects of a combination of liraglutide and insulin on fracture healing in a rat model of diabetes and the mechanisms involved. Closed femoral mid-shaft fractures were established in male Sprague-Dawley rats with or without diabetes mellitus, and the diabetic rats were administered insulin and/or liraglutide. Six weeks after femoral fracture, the femoral callus was evaluated by immunohistochemistry, histology, and micro-computed tomography. Additionally, the effects of liraglutide on high-glucose-stimulated MC3T3-E1 cells were analyzed by Western blotting. Micro-computed tomography and safranin O/fast green staining showed that fracture healing was delayed in the diabetic rats, and this was accompanied by much lower expression of osteogenic markers and greater osteoclast activity. However, treatment with insulin and/or liraglutide prevented these changes. Liraglutide in combination with insulin treatment resulted in lower blood glucose concentrations and significantly higher osteocalcin (OCN) and collagen I (Col I) expression six weeks following fracture. Western blot analysis showed that liraglutide prevented the low expression of the bone morphogenetic protein-2, osterix/SP7, OCN, Col I, and β-catenin in high-glucose-stimulated MC3T3-E1 cells. These results demonstrate that insulin and/or liraglutide promotes bone fracture healing in the DF model. The combination was more effective than either single treatment, which may be because of the two drugs' additive effects on the osteogenic ability of osteoblast precursors.