• Antisense morpholino
• Dickkopf-1
• Osteosarcoma
• Wnt

• Osteosarcoma/metabolism
• Osteosarcoma/pathology
• Osteosarcoma/genetics
• Osteosarcoma/mortality
• Animals
• Intercellular Signaling Peptides and Proteins/metabolism
• Intercellular Signaling Peptides and Proteins/genetics
• Bone Neoplasms/metabolism
• Bone Neoplasms/secondary
• Bone Neoplasms/pathology
• Bone Neoplasms/genetics
• Mice
• Cell Line, Tumor
• Humans
• Wnt Signaling Pathway
• Aldehyde Dehydrogenase 1 Family/metabolism
• Aldehyde Dehydrogenase 1 Family/genetics
• Retinal Dehydrogenase/metabolism
• Retinal Dehydrogenase/genetics
• Neoplasm Metastasis
• Gene Expression Regulation, Neoplastic
• Osteogenesis

• RP170496, RP160765 Cancer Prevention and Research Institute of Texas

• PPAR gamma/metabolism
• Animals
• Osteoporosis/drug therapy
• Mice
• Diterpenes, Clerodane/pharmacology
• Diterpenes, Clerodane/chemistry
• Diterpenes, Clerodane/chemical synthesis
• Diterpenes, Clerodane/therapeutic use
• Structure-Activity Relationship
• Osteogenesis/drug effects
• Osteoclasts/drug effects
• Osteoclasts/metabolism
• Humans
• Drug Discovery
• Molecular Docking Simulation

• GelMA
• antibacterial
• barium titanate
• bone regeneration
• electrical charges
• hydrogel
• multifunctional
• periodontal disease
• periodontium
• piezoelectric

• Animals
• Mice
• Hydrogels/pharmacology
• Osteogenesis
• Periodontal Diseases/drug therapy
• Periodontium
• Anti-Bacterial Agents/pharmacology

• Tideglusib
• Wnt/β-catenin
• dental pulp cell
• odonto/osteogenic differentiation

6-bromoindirubin-3′-oxime (BIO) is a candidate small molecule that effectively modulates Wnt signalling owing to its stable property. The present study investigated the influence of BIO on the odonto/osteogenic differentiation of human dental pulp stem cells (hDPSCs). hDPSCs were treated with 200, 400, or 800 nM BIO, and the effects on hDPSC responses and osteogenic differentiation were assessed. BIO-mediated Wnt activation was confirmed by β-catenin nuclear translocation detected by immunofluorescence staining. BIO attenuated colony formation and cell migration determined by in vitro wound-healing assay. BIO increased early apoptotic cell population evaluated using flow cytometry. For osteogenic induction, BIO promoted alkaline phosphatase (ALP) activity and mineralisation in a dose-dependent manner. ALP, RUNX2, OCN, OSX, ANKH, DMP1, and DSPP mRNA expression were significantly upregulated. The OPG/RANKL expression ratio was also increased. Further, BIO attenuated adipogenic differentiation as demonstrated by decreased lipid accumulation and adipogenic-related gene expression. Bioinformatic analysis of RNA sequencing data from the BIO-treated hDPSCs revealed that BIO modulated pathways related to autophagy and actin cytoskeleton regulation. These findings demonstrated that BIO treatment promoted hDPSC osteogenic differentiation. Therefore, this small molecule is a strong candidate as a bioactive molecule to enhance dentin repair.

• Biomaterial
• immune system
• immunocompatibility
• regenerative medicine
• tissue engineering

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.

• GCN5 HAT
• TiO2 nanotube
• Wnt/β-catenin signaling pathway
• bone marrow stromal cells
• osteogenic differentiation

• Wnt
• beta-catenin
• bone regeneration
• nanoparticulate mineralized collagen glycosaminoglycan
• stiffness

• Cell Differentiation
• Cells, Cultured
• Humans
• Mechanotransduction, Cellular
• Mesenchymal Stem Cells/metabolism
• Osteogenesis
• Wnt Signaling Pathway
• beta Catenin/metabolism

• R01 DE028098 NIDCR NIH HHS
• R01 DE029234 NIDCR NIH HHS
• R21 DE026582 NIDCR NIH HHS

• INFH
• LRRC17
• Wnt signaling pathways
• femoral neck fracture
• mesenchymal stem cells

• Osteoblastic differentiation
• PPAR-γ
• SFRP5
• Wnt/β-catenin signaling pathway

• Adipokines/genetics
• Adipokines/metabolism
• Animals
• Cell Differentiation
• Dexamethasone/adverse effects
• Female
• Gene Knockdown Techniques
• Mesenchymal Stem Cells/metabolism
• Models, Biological
• Osteogenesis
• Osteoporosis/chemically induced
• Osteoporosis/metabolism
• PPAR gamma/metabolism
• Rats
• Rats, Sprague-Dawley
• Transcription, Genetic
• Wnt Signaling Pathway

• Animals
• Bone and Bones/cytology
• Cell Division
• Humans
• Mice
• Osteogenesis
• Skull/cytology
• Skull/physiology
• Stem Cells/cytology
• Tissue Engineering/methods
• Wnt Proteins/metabolism

• 102513/Z/13/Z Wellcome Trust
• Department of Health
• MR/K017047/1 Medical Research Council
• BB/R015953/1 Biotechnology and Biological Sciences Research Council
• MR/R015635/1 Medical Research Council

• 6-bromoindirubin-3′-oxime
• alveolar bone regeneration
• osteogenic differentiation
• periodontal ligament stem cells
• periodontitis

• GSK3 inhibitor
• Osteotropic
• Periodontitis
• Pluronic F127
• Pyrophosphate
• Thermoresponsive hydrogel

• Animals
• Glycogen Synthase Kinase 3
• Hydrogels
• Periodontitis/drug therapy
• Periodontium
• Poloxamer
• Rats

• P20 GM103480 NIGMS NIH HHS
• P30 GM127200 NIGMS NIH HHS
• R01 AI119090 NIAID NIH HHS

Engineered bone graft designs have been largely inspired by adult bone despite functionally significant differences from the composition of anabolic bone in both the mineralized and non-mineralized fractions. Specifically, anabolic bone contains hydroxyapatite with ionic substitutions that facilitate bone turnover and relatively rare collagens type VI and XII that are important for normal bone development. In this work, human mesenchymal stem cells (hMSCs) were cultured in lyophilized collagen type I scaffolds mineralized with hydroxyapatite containing Mg²⁺ substitutions, then induced to deposit an extracellular matrix (ECM) containing collagens VI and XII by exposure to GW9662, a PPARγ inhibitor. Delivery of GW9662 was accomplished through either Supplemented Media or via composite microspheres embedded in the scaffolds for localized delivery. Furthermore, hMSCs and scaffolds were cultured in both static and perfuse conditions to investigate the interaction between GW9662 treatment and perfusion and their effects on ECM deposition trends. Perfusion culture enhanced cell infiltration into the scaffold, deposition of collagen VI and XII, as well as osteogenic differentiation, as determined by gene expression of osteopontin, BMP2, and ALP. Furthermore, scaffold mineral density and compressive modulus were increased in response to both GW9662 treatment and perfusion after 3 weeks of culture. Local delivery of GW9662 with drug-eluting microspheres had comparable effects to systemic delivery in the perfusate. Together, these results demonstrate a strategy to create a scaffold mimicking both organic and inorganic characteristics of anabolic bone and its potential as a bone graft.

• biomimetic
• bioreactor
• bone
• drug-delivery
• extracellular matrix
• mesenchymal stem cells

Approximately 10% of fractures will not heal without intervention. Current treatments can be marginally effective, costly, and some have adverse effects. A safe and manufacturable mimic of anabolic bone is the primary goal of bone engineering, but achieving this is challenging. Mesenchymal stem cells (MSCs), are excellent candidates for engineering bone, but lack reproducibility due to donor source and culture methodology. The need for a bioactive attachment substrate also hinders progress. Herein, we describe a highly osteogenic MSC line generated from induced pluripotent stem cells that generates high yields of an osteogenic cell-matrix (ihOCM) in vitro. In mice, the intrinsic osteogenic activity of ihOCM surpasses bone morphogenic protein 2 (BMP2) driving healing of calvarial defects in 4 weeks by a mechanism mediated in part by collagen VI and XII. We propose that ihOCM may represent an effective replacement for autograft and BMP products used commonly in bone tissue engineering.

Production of a safe and manufacturable material to mimic anabolic bone for tissue engineering has been hard to achieve to date. Here the authors use a mesenchymal stem cell line generated from induced pluripotent stem cells to produce osteogenic cell-matrix, displaying significant healing properties in mice.

• Cell-material interactions
• Human mesenchymal stem cells
• Hydrogel
• Integrin
• Matrix remodeling
• Poly(ethylene glycol)

• Cell Proliferation/drug effects
• Extracellular Matrix Proteins
• Humans
• Hydrogels/chemistry
• Hydrogels/pharmacology
• Integrin alpha5beta1/metabolism
• Mesenchymal Stem Cells/cytology
• Mesenchymal Stem Cells/metabolism
• Oligopeptides/chemistry
• Oligopeptides/pharmacology
• Polyethylene Glycols/chemistry
• Polyethylene Glycols/pharmacology
• Porosity
• Signal Transduction/drug effects

• R21 AR071625 NIAMS NIH HHS

• Bone
• Extracellular matrix
• Osteogenesis
• Osteogenic
• Purification
• Tissue culture

• Alkaline Phosphatase/metabolism
• Animals
• Biomarkers/metabolism
• Calcification, Physiologic
• Cell Adhesion
• Cells, Cultured
• Extracellular Matrix/metabolism
• Extracellular Matrix/ultrastructure
• Humans
• Mesenchymal Stem Cells/cytology
• Osteogenesis
• Swine
• Tissue Engineering/methods

• R01 AR066033 NIAMS NIH HHS
• R21 AR072292 NIAMS NIH HHS

• BMP
• Bone regeneration
• GapmeR
• LNA-ASO
• Mesenchymal stem cells
• Osteogenesis
• Smurf1

• Alginates/chemistry
• Animals
• Bone Morphogenetic Protein 2/genetics
• Bone Morphogenetic Protein 2/metabolism
• Bone Regeneration
• Cell Differentiation
• Cells, Cultured
• Female
• Gene Silencing
• Humans
• Lipids/chemistry
• Mesenchymal Stem Cells/cytology
• Mesenchymal Stem Cells/metabolism
• Nanoparticles/administration & dosage
• Oligonucleotides/genetics
• Oligonucleotides, Antisense/genetics
• Rats
• Rats, Sprague-Dawley
• Skull/growth & development
• Skull/injuries
• Skull/metabolism
• Tissue Engineering/methods
• Ubiquitin-Protein Ligases/antagonists & inhibitors
• Ubiquitin-Protein Ligases/genetics

Platelet-rich fibrin (PRF) is a platelet concentrate derived from complete autologous blood rich in growth factors in the fibrin matrix. Although PRF has been used during oral surgery to optimize wound healing in soft and hard tissue, the precise role of PRF in bone healing remains unclear. The present study assessed the role of PRF in bone remodeling. PRF was prepared from whole blood by low speed centrifugation without any anti-coagulants. Culture of MC3T3-E1 cells with PRF induced the expression of osteoprotegerin (OPG), but had no effect on the expression of receptor activator of nuclear factor-κB ligand (RANKL), increasing the OPG/RANKL ratio. Expression of other osteoblastic differentiation makers, including BMP-2 and −4 and RUNX2, was not affected. PRF filling of a hole defect in the mental foramen bone of rats increased OPG positivity and decreased tartrate-resistant acid phosphatase positivity compared with unfilled control. In conclusion, PRF increased the OPG/RANKL ratio by inducing OPG expression, suggesting that PRF enhances early stage osteogenesis by optimizing osteoblastic differentiation. The present study provides a scientific basis for clinical findings showing that PRF can enhance bone regeneration such as sinus lift.

• MC3T3-E1
• bone defect-healing
• osteoblastic differentiation
• osteoprotegerin
• platelet-rich fibrin

• Osteogenesis
• Peroxisome proliferator-activated receptor gamma 2
• Porcine skin-derived stem cells
• Spontaneous adipocyte generation

Bone marrow mesenchymal stem/stromal cells (MSCs) maintain bone homeostasis and repair through the ability to expand in response to mitotic stimuli and differentiate into skeletal lineages. Signalling mechanisms that enable precise control of MSC function remain unclear. Here we report that by initially examining differences in signalling pathway expression profiles of individual MSC clones, we identified a previously unrecognised signalling mechanism regulated by epidermal growth factor (EGF) in primary human MSCs. We demonstrate that EGF is able to activate β-catenin, a key component of the canonical Wnt signalling pathway. EGF is able to induce nuclear translocation of β-catenin in human MSCs but does not drive expression of Wnt target genes or T cell factor (TCF) activity in MSC reporter cell lines. Using an efficient Design of Experiments (DoE) statistical analysis, with different combinations and concentrations of EGF and Wnt ligands, we were able to confirm that EGF does not influence the Wnt/β-catenin pathway in MSCs. We show that the effects of EGF on MSCs are temporally regulated to initiate early “classical” EGF signalling mechanisms (e.g via mitogen activated protein kinase) with delayed activation of β-catenin. By RNA-sequencing, we identified gene sets that were exclusively regulated by the EGF/β-catenin pathway, which were distinct from classical EGF-regulated genes. However, subsets of classical EGF gene targets were significantly influenced by EGF/β-catenin activation. These signalling pathways cooperate to enable EGF-mediated proliferation of MSCs by alleviating the suppression of cell cycle pathways induced by classical EGF signalling.

•

Epidermal growth factor (EGF) controls mesenchymal stem cell (MSC) proliferation.

• Epidermal growth factor
• Integrin-linked kinase
• Mesenchymal stem cells
• β-Catenin

• Cell Line
• Cell Proliferation
• Epidermal Growth Factor/metabolism
• Humans
• Mesenchymal Stem Cells/cytology
• Mesenchymal Stem Cells/metabolism
• Wnt Signaling Pathway
• beta Catenin/metabolism

• 20575 Arthritis Research UK
• Biotechnology and Biological Sciences Research Council
• 19429 Arthritis Research UK
• Medical Research Council
• 20575 Versus Arthritis

• Bone metastasis
• Cancer therapeutics
• Osteogenesis
• Osteolysis
• Wnt signaling

• Drug delivery
• Polymersomes
• Wnt

Hair cell (HC) loss is the main cause of permanent hearing loss in mammals. Previous studies have reported that in neonatal mice cochleae, Wnt activation promotes supporting cell (SC) proliferation and Notch inhibition promotes the trans-differentiation of SCs into HCs. However, Wnt activation alone fails to regenerate significant amounts of new HCs, Notch inhibition alone regenerates the HCs at the cost of exhausting the SC population, which leads to the death of the newly regenerated HCs. Mitotic HC regeneration might preserve the SC number while regenerating the HCs, which could be a better approach for long-term HC regeneration. We present a two-step gene manipulation, Wnt activation followed by Notch inhibition, to accomplish mitotic regeneration of HCs while partially preserving the SC number. We show that Wnt activation followed by Notch inhibition strongly promotes the mitotic regeneration of new HCs in both normal and neomycin-damaged cochleae while partially preserving the SC number. Lineage tracing shows that the majority of the mitotically regenerated HCs are derived specifically from the Lgr5⁺ progenitors with or without HC damage. Our findings suggest that the co-regulation of Wnt and Notch signaling might provide a better approach to mitotically regenerate HCs from Lgr5⁺ progenitor cells.

• Notch
• Wnt
• lineage tracing
• proliferation
• regeneration

Non‐union defects of bone are a major problem in orthopedics, especially for patients with a low healing capacity. Fixation devices and osteoconductive materials are used to provide a stable environment for osteogenesis and an osteogenic component such as autologous human bone marrow (hBM) is then used, but robust bone formation is contingent on the healing capacity of the patients. A safe and rapid procedure for improvement of the osteoanabolic properties of hBM is, therefore, sought after in the field of orthopedics, especially if it can be performed within the temporal limitations of the surgical procedure, with minimal manipulation, and at point‐of‐care. One way to achieve this goal is to stimulate canonical Wingless (cWnt) signaling in bone marrow‐resident human mesenchymal stem cells (hMSCs), the presumptive precursors of osteoblasts in bone marrow. Herein, we report that the effects of cWnt stimulation can be achieved by transient (1–2 hours) exposure of osteoprogenitors to the GSK3β‐inhibitor (2′Z,3′E)‐6‐bromoindirubin‐3′‐oxime (BIO) at a concentration of 800 nM. Very‐rapid‐exposure‐to‐BIO (VRE‐BIO) on either hMSCs or whole hBM resulted in the long‐term establishment of an osteogenic phenotype associated with accelerated alkaline phosphatase activity and enhanced transcription of the master regulator of osteogenesis, Runx2. When VRE‐BIO treated hBM was tested in a rat spinal fusion model, VRE‐BIO caused the formation of a denser, stiffer, fusion mass as compared with vehicle treated hBM. Collectively, these data indicate that the VRE‐BIO procedure may represent a rapid, safe, and point‐of‐care strategy for the osteogenic enhancement of autologous hBM for use in clinical orthopedic procedures. stemcellstranslationalmedicine2018;7:342–353

• Bone marrow
• Bromo-indirubin-monooxime
• Osteogenesis
• Spine fusion
• Stem cells

The utilization of self-assembled monolayer (SAM) systems to direct Mesenchymal Stem Cell (MSC) differentiation has been covered in the literature for years, but finding a general consensus pertaining to its exact role over the differentiation of stem cells had been rather challenging. Although there are numerous reports on surface functional moieties activating and inducing differentiation, the results are often different between reports due to the varying surface conditions, such as topography or surface tension. Herein, in view of the complexity of the subject matter, we have sought to catalogue the recent developments around some of the more common functional groups on predominantly hard surfaces and how these chemical groups may influence the overall outcome of the mesenchymal stem cells (MSC) differentiation so as to better establish a clearer underlying relationship between stem cells and their base substratum interactions.

Graphical illustration showing the functional groups that drive MSC differentiation without soluble bioactive cues within the first 14 days.

• Animals
• Cardiovascular Diseases/drug therapy
• Cardiovascular Diseases/metabolism
• Humans
• Molecular Targeted Therapy
• Wnt Signaling Pathway/drug effects
• Wnt Signaling Pathway/physiology

• R01 HL129178 NHLBI NIH HHS
• R01 HL137241 NHLBI NIH HHS

Orthodontic force-induced osteogenic differentiation and bone formation at tension sites play a critical role in orthodontic tooth movement. However, the molecular mechanism underlying this phenomenon is poorly understood. In the current study, we investigated the involvement of the GSK-3β/β-catenin signaling pathway, which is critical for bone formation during tooth movement. We established a rat tooth movement model to test the hypothesis that orthodontic force may stimulate bone formation at the tension site of the moved tooth and promote the rate of tooth movement via regulation of the GSK-3β/β-catenin signaling pathway. Our results showed that continued mechanical loading increased the distance between the first and second molar in rats. In addition, the loading force increased bone formation at the tension site, and also increased phospho-Ser9-GSK-3β expression and β-catenin signaling pathway activity. Downregulation of GSK-3β activity further increased bone parameters, including bone mineral density, bone volume to tissue volume and trabecular thickness, as well as ALP- and osterix-positive cells at tension sites during tooth movement. However, ICG-001, the β-catenin selective inhibitor, reversed the positive effects of GSK-3β inhibition. In addition, pharmaceutical inhibition of GSK-3β or local treatment with β-catenin inhibitor did not influence the rate of tooth movement. Based on these results, we concluded that GSK-3β/β-catenin signaling contributes to the bone remodeling induced by orthodontic forces, and can be used as a potential therapeutic target in clinical dentistry.

• Bone formation
• GSK-3β/β-catenin signaling pathway
• Orthodontic force
• Orthodontic tooth movement
• Osteogenic differentiation

The dog represents an excellent large animal model for translational cell-based studies. Importantly, the properties of canine multipotent stromal cells (cMSCs) and the ideal tissue source for specific translational studies have yet to be established. The aim of this study was to characterize cMSCs derived from synovium, bone marrow, and adipose tissue using a donor-matched study design and a comprehensive series of in-vitro characterization, differentiation, and immunomodulation assays.

Canine MSCs were isolated from five dogs with cranial cruciate ligament rupture. All 15 cMSC preparations were evaluated using colony forming unit (CFU) assays, flow cytometry analysis, RT-PCR for pluripotency-associated genes, proliferation assays, trilineage differentiation assays, and immunomodulation assays. Data were reported as mean ± standard deviation and compared using repeated-measures analysis of variance and Tukey post-hoc test. Significance was established at p < 0.05.

All tissue samples produced plastic adherent, spindle-shaped preparations of cMSCs. Cells were negative for CD34, CD45, and STRO-1 and positive for CD9, CD44, and CD90, whereas the degree to which cells were positive for CD105 was variable depending on tissue of origin. Cells were positive for the pluripotency-associated genes NANOG, OCT4, and SOX2. Accounting for donor and tissue sources, there were significant differences in CFU potential, rate of proliferation, trilineage differentiation, and immunomodulatory response. Synovium and marrow cMSCs exhibited superior early osteogenic activity, but when assessing late-stage osteogenesis no significant differences were detected. Interestingly, bone morphogenic protein-2 (BMP-2) supplementation was necessary for early-stage and late-stage osteogenic differentiation, a finding consistent with other canine studies. Additionally, synovium and adipose cMSCs proliferated more rapidly, displayed higher CFU potential, and formed larger aggregates in chondrogenic assays, although proteoglycan and collagen type II staining were subjectively decreased in adipose pellets as compared to synovial and marrow pellets. Lastly, cMSCs derived from all three tissue sources modulated murine macrophage TNF-α and IL-6 levels in a lipopolysaccharide-stimulated coculture assay.

While cMSCs from synovium, marrow, and adipose tissue share a number of similarities, important differences in proliferation and trilineage differentiation exist and should be considered when selecting cMSCs for translational studies. These results and associated methods will prove useful for future translational studies involving the canine model.

The online version of this article (doi:10.1186/s13287-017-0639-6) contains supplementary material, which is available to authorized users.

• Adipose tissue
• Bone marrow
• Canine
• Characterization
• Differentiation
• Immunomodulation
• Multipotent stromal cells
• Synovium

It is a great challenge to prepare “functional artificial bone” for the repair of large segmental defect, especially in weight-bearing bones. In this study, bioactive HA/PCL composite scaffolds that possess anatomical structure as autogenous bone were fabricated by CT-guided fused deposition modeling technique. The scaffolds can provide mechanical support and possess osteoconduction property. Then the VEGF-165/BMP-2 loaded hydrogel was filled into biomimetic artificial bone spatially to introduce osteoinduction and angioinduction ability via sustained release of these cytokines. It has been revealed that the cytokine-loaded hydrogel possessed good biodegradability and could release the VEGF-165/BMP-2 sustainedly and steadily. The synergistic effect of these two cytokines showed significant stimulation on the osteogenic gene expresssion of osteoblast in vitro and ectopic ossification in vivo. The scaffolds were then implanted into the rabbit tibial defect sites (1.2 cm) for bone regeneration for 12 weeks, indicating the best repair of defect in vivo, which was superior to the pure hydrogel/scaffolds or one-cytokine loaded hydrogel/scaffolds and close to autogenous bone graft. The strategy to construct an “anatomy-structure-function” trinity system as functional artificial bone shows great potential in replacing autogenous bone graft and applying in large bone defect repair clinically in future.

• Anabolics
• Nutrition
• Preclinical studies
• Stromal/stem cells
• Theobromine

• Animals
• Bone Development/drug effects
• Bone and Bones/cytology
• Bone and Bones/drug effects
• Cell Differentiation/drug effects
• Cells, Cultured
• Humans
• Mesenchymal Stem Cells/drug effects
• Mesenchymal Stem Cells/metabolism
• Osteogenesis/drug effects
• Rats
• Theobromine/pharmacology
• Up-Regulation/drug effects

• P40 RR017447 NCRR NIH HHS

• Adult stem cells
• Animal model
• Scaffolds
• Stem cells
• Tissue engineering
• Vertebral fusion

• bone regeneration
• controlled release
• degradable polymer
• inflammation
• protein nanocapsule

• Bone Regeneration
• Delayed-Action Preparations
• Nanocapsules
• Polymers

• Bone mineral density
• Carcinoembryonic antigen-related adhesion molecule 1
• Postmenopausal osteoporosis
• β-catenin

• Absorptiometry, Photon/methods
• Aged
• Antigens, CD/blood
• Antigens, CD/physiology
• Bone Density/physiology
• Bone Diseases, Metabolic/blood
• Bone Diseases, Metabolic/physiopathology
• Cell Adhesion Molecules/blood
• Cell Adhesion Molecules/physiology
• Female
• Femur Neck/diagnostic imaging
• Femur Neck/physiopathology
• Humans
• Lumbar Vertebrae/diagnostic imaging
• Lumbar Vertebrae/physiopathology
• Middle Aged
• Osteoporosis, Postmenopausal/blood
• Osteoporosis, Postmenopausal/diagnostic imaging
• Osteoporosis, Postmenopausal/physiopathology
• beta Catenin/blood

Matrix-bound BMP-2 is sufficient to induce β3 integrin–dependent, Cdc42/Src/FAK/ILK-mediated cell spreading by overriding the stiffness response through actin and adhesion site dynamics, showing BMP receptors and integrins work together to control signaling and tensional homeostasis, thereby coupling cell adhesion and fate commitment.

Understanding how cells integrate multiple signaling pathways to achieve specific cell differentiation is a challenging question in cell biology. We have explored the physiological presentation of BMP-2 by using a biomaterial that harbors tunable mechanical properties to promote localized BMP-2 signaling. We show that matrix-bound BMP-2 is sufficient to induce β3 integrin–dependent C2C12 cell spreading by overriding the soft signal of the biomaterial and impacting actin organization and adhesion site dynamics. In turn, αvβ3 integrin is required to mediate BMP-2–induced Smad signaling through a Cdc42–Src–FAK–ILK pathway. β3 integrin regulates a multistep process to control first BMP-2 receptor activity and second the inhibitory role of GSK3 on Smad signaling. Overall, our results show that BMP receptors and β3 integrin work together to control Smad signaling and tensional homeostasis, thereby coupling cell adhesion and fate commitment, two fundamental aspects of developmental biology and regenerative medicine.

• Adipogenesis
• Animals
• Bone Morphogenetic Protein 2/metabolism
• Bone Regeneration/physiology
• Calcium-Binding Proteins
• Humans
• Male
• Mesenchymal Stem Cells/metabolism
• Nerve Tissue Proteins/metabolism
• Osteogenesis/physiology
• Rats, Inbred Lew
• Signal Transduction/physiology

• T32 DE007296 NIDCR NIH HHS
• R01 DE01607 NIDCR NIH HHS
• 5T32DE007296-14 NIDCR NIH HHS
• R01 AR061399-01A1 NIAMS NIH HHS
• R21 DE0177711 NIDCR NIH HHS
• R01 AR061399 NIAMS NIH HHS

• Adipocytes
• Beige fat
• Brown fat
• Osteocalcin
• PPARG
• Sympathetic tone

• Adipocytes/metabolism
• Adipose Tissue, Brown/metabolism
• Animals
• Bone Density/physiology
• Diabetes Mellitus, Type 2/metabolism
• Energy Metabolism/physiology
• Homeostasis/physiology
• Humans
• Translational Research, Biomedical/trends

• P30 GM106391 NIGMS NIH HHS
• R24 DK092759 NIDDK NIH HHS
• R21 AR066120 NIAMS NIH HHS
• R24 DK084970 NIDDK NIH HHS
• R24DK092759-05 NIDDK NIH HHS
• P30 DK020572 NIDDK NIH HHS

Activation of the canonical Wnt signaling pathway is an attractive anabolic therapeutic strategy for bone. Emerging data suggest that activation of the Wnt signaling pathway promotes bone mineral accrual in osteoporotic patients. The effect of Wnt stimulation in fracture healing is less clear as Wnt signaling has both stimulatory and inhibitory effects on osteogenesis. Here, we tested the hypothesis that transient Wnt stimulation promotes the expansion and osteogenesis of a Wnt‐responsive stem cell population present in human bone marrow. Bone marrow mononuclear cells (BMMNCs) were isolated from patients undergoing hip arthroplasty and exposed to Wnt3A protein. The effect of Wnt pathway stimulation was determined by measuring the frequency of stem cells within the BMMNC populations by fluorescence‐activated cell sorting and colony forming unit fibroblast (CFU‐F) assays, before determining their osteogenic capacity in in vitro differentiation experiments. We found that putative skeletal stem cells in BMMNC isolates exhibited elevated Wnt pathway activity compared with the population as whole. Wnt stimulation resulted in an increase in the frequency of skeletal stem cells marked by the STRO‐1^bright/Glycophorin A⁻ phenotype. Osteogenesis was elevated in stromal cell populations arising from BMMNCs transiently stimulated by Wnt3A protein, but sustained stimulation inhibited osteogenesis in a concentration‐dependent manner. These results demonstrate that Wnt stimulation could be used as a therapeutic approach by transient targeting of stem cell populations during early fracture healing, but that inappropriate stimulation may prevent osteogenesis. Stem Cells2016;34:418–430

• Fracture healing
• Marrow stromal cells/mesenchymal stem cells
• Osteoprogenitors
• Stem cells
• Wnt signaling

• Aged
• Aged, 80 and over
• Arthroplasty, Replacement, Hip
• Bone Marrow Cells/cytology
• Bone Marrow Cells/metabolism
• Female
• Flow Cytometry
• Humans
• Leukocytes, Mononuclear/cytology
• Leukocytes, Mononuclear/metabolism
• Male
• Middle Aged
• Osteogenesis
• Stem Cells/cytology
• Stem Cells/metabolism
• Stromal Cells/cytology
• Stromal Cells/metabolism
• Wnt Signaling Pathway
• Wnt3A Protein/metabolism

• MR/J004103/1 Medical Research Council

• bone fracture
• gsk3β inhibitor
• 6-bromoindirubin-3’-oxime
• biodistribution
• micelles
• octaaspartic acid

• Animals
• Drug Carriers
• Fracture Healing/drug effects
• Glycogen Synthase Kinase 3/antagonists & inhibitors
• Glycogen Synthase Kinase 3 beta
• Mice
• Micelles
• Protein Kinase Inhibitors/pharmacokinetics
• Protein Kinase Inhibitors/pharmacology
• Tissue Distribution
• Tomography, Emission-Computed, Single-Photon
• Tomography, X-Ray Computed

• R01 GM069847 NIGMS NIH HHS
• R01 GM69847 NIGMS NIH HHS

MicroRNAs (miRNAs) emerge as important regulators of stem cell lineage commitment and bone development. MiRNA-26a (miR-26a) is one of the important miRNAs regulating osteogenic differentiation of both bone marrow-derived mesenchymal stem cells (BMSCs) and adipose tissue-derived mesenchymal stem cells (ADSCs). However, miR-26a functions oppositely in osteogenic differentiation of BMSCs and ADSCs, suggesting distinct post-transcriptional regulation of tissue-specific MSC differentiation. However, the molecular basis is largely unknown. Here, we report that the function of miR-26a is largely depended on the intrinsic signaling regulation network of MSCs. Using bioinformatics and functional assay, we confirmed that miR-26a potentially targeted on GSK3β and Smad1 to regulate Wnt and BMP signaling pathway. Overall comparative analysis revealed that Wnt signaling was enhanced more potently and played a more important role than BMP signaling in osteogenic differentiation of BMSCs, whereas BMP pathway was more essential for promoting osteogenic differentiation of ADSCs. The distinct activation pattern and role of signaling pathways determined that miR-26a majorly targeted on GSK3β to activate Wnt signaling for promoting osteogenic differentiation of BMSCs, whereas it inhibited Smad1 to suppress BMP signaling for interfering with the osteogenic differentiation of ADSCs. Taken together, our study demonstrated that BMSCs and ADSCs applied different signaling pathway to facilitate their osteogenic differentiation, which determined the inverse function of miR-26a. The distinct transcriptional regulation and post-transcriptional regulation network suggested the intrinsic molecular differences between tissue-specific MSCs and the complexity in MSC research and MSC-based cell therapy.

• Lithium chloride
• Osteoblast
• Osteoclast
• Osteolysis
• Wear debris

• Animals
• Female
• Glycogen Synthase Kinase 3/antagonists & inhibitors
• Glycogen Synthase Kinase 3/metabolism
• Glycogen Synthase Kinase 3 beta
• Lithium Chloride/therapeutic use
• Mice
• Mice, Inbred C57BL
• Osteolysis/drug therapy
• Osteolysis/enzymology
• Osteolysis/etiology
• Osteolysis/pathology
• Prostheses and Implants/adverse effects
• Protein Kinase Inhibitors/therapeutic use
• Skull/drug effects
• Skull/enzymology
• Skull/pathology
• Titanium/adverse effects