Bone morphogenetic protein-9 effectively induces osteogenic differentiation of reversibly immortalized calvarial mesenchymal progenitor cells

Hmga1-overexpressing lentivirus protects against osteoporosis by activating the Wnt/β-catenin pathway in the osteogenic differentiation of BMSCs

Postmenopausal osteoporosis is associated with bone formation inhibition mediated by the impaired osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs). However, identifying and confirming the essential genes in the osteogenic differentiation of BMSCs and osteoporosis remain challenging. The study aimed at revealing the key gene that regulated osteogenic differentiation of BMSCs and led to osteoporosis, thus exploring its therapeutic effect in osteoporosis. In the present study, six essential genes related to the osteogenic differentiation of BMSCs and osteoporosis were identified, namely, fibrillin 2 (Fbn2), leucine-rich repeat-containing 17 (Lrrc17), heat shock protein b7 (Hspb7), high mobility group AT-hook 1 (Hmga1), nexilin F-actin-binding protein (Nexn), and endothelial cell-specific molecule 1 (Esm1). Furthermore, the in vivo and in vitro experiments showed that Hmga1 expression was increased during the osteogenic differentiation of rat BMSCs, while Hmga1 expression was decreased in the bone tissue of ovariectomized (OVX) rats. Moreover, the expression of osteogenic differentiation-related genes, the activity of alkaline phosphatase (ALP), and the number of mineralized nodules were increased after Hmga1 overexpression, which was partially reversed by a Wnt signaling inhibitor (DKK1). In addition, after injecting Hmga1-overexpressing lentivirus into the bone marrow cavity of OVX rats, the bone loss, and osteogenic differentiation inhibition of BMSCs in OVX rats were partially reversed, while osteoclast differentiation promotion of BMSCs in OVX rats was unaffected. Taken together, the present study confirms that Hmga1 prevents OVX-induced bone loss by the Wnt signaling pathway and reveals that Hmga1 is a potential gene therapeutic target for postmenopausal osteoporosis.

Osteogenic Differentiation Effect of BMP-9 with Phenamil and Simvastatin on Intact Human Amniotic Epithelial Stem Cells

Background

Background: Bone tissue engineering has shown to be a promising strategy for repairing bone defects without causing harmful side effects to the patient. Three main building blocks of tissue engineering, including seeding cells, scaffold, and signaling molecules, are required for adequate bone regeneration. The human amniotic membrane (hAM) is the innermost of the placental membranes. In addition to providing a source of stem cells and growth factors, hAM has several features that make it an appropriate scaffold containing stem cells for use in tissue engineering purposes. The present investigation aimed to assess the effect of bone morphogenetic protein-9 (BMP-9) combined with phenamil and simvastatin on osteogenic induction of hAM with its human amniotic membrane epithelial cells (hAECs).

Method

Methods: Using six different osteogenic medium (OMs), we cultured hAM for 14 days. The basic OMs were chosen as the first group and other media were made by adding BMP-9, phenamil, simvastatin, BMP-9 alongside phenamil, and BMP-9 alongside simvastatin to the basic OMs. Finally, viability assay, tissue mineralization, calcium and phosphate content determination, and measurement of lactic acid dehydrogenase (LDH), and alkaline phosphatase (ALP) activity were performed.

Results

Results: Among all study groups, groups containing simvastatin showed a significantly lower level of viability. Although all media could induce osteogenic features, the hAECs cultured in media containing BMP-9 and phenamil demonstrated a wider area of mineralization and a significantly higher level of calcium and phosphate content, LDH, and ALP activity.

Conclusion

Conclusion: Our findings indicated that the use of phenamil together with BMP-9 could synergistically show in situ osteogenic induction in hAECs, which could be a new insight into translational medicine.

Bone Morphogenetic Protein-9-Stimulated Adipocyte-Derived Mesenchymal Progenitors Entrapped in a Thermoresponsive Nanocomposite Scaffold Facilitate Cranial Defect Repair

Due to availability and ease of harvest, adipose tissue is a favorable source of progenitor cells in regenerative medicine, but has yet to be optimized for osteogenic differentiation. The purpose of this study was to test cranial bone healing in a surgical defect model utilizing bone morphogenetic protein-9 (BMP-9) transduced immortalized murine adipocyte (iMAD) progenitor cells in a citrate-based, phase-changing, poly(polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN)-gelatin scaffold. Mesenchymal progenitor iMAD cells were transduced with adenovirus expressing either BMP-9 or green fluorescent protein control. Twelve mice underwent craniectomy to achieve a critical-sized cranial defect. The iMAD cells were mixed with the PPCN-gelatin scaffold and injected into the defects. MicroCT imaging was performed in 2-week intervals for 12 weeks to track defect healing. Histologic analysis was performed on skull sections harvested after the final imaging at 12 weeks to assess quality and maturity of newly formed bone. Both the BMP-9 group and control group had similar initial defect sizes (P = 0.21). At each time point, the BMP-9 group demonstrated smaller defect size, higher percentage defect healed, and larger percentage defect change over time. At the end of the 12-week period, the BMP-9 group demonstrated mean defect closure of 27.39%, while the control group showed only a 9.89% defect closure (P < 0.05). The BMP-9-transduced iMADs combined with a PPCN-gelatin scaffold promote in vivo osteogenesis and exhibited significantly greater osteogenesis compared to control. Adipose-derived iMADs are a promising source of mesenchymal stem cells for further studies in regenerative medicine, specifically bone engineering with the aim of potential craniofacial applications.

Acceleration of Bone Regeneration in Critical-Size Defect Using BMP-9-Loaded nHA/ColI/MWCNTs Scaffolds Seeded with Bone Marrow Mesenchymal Stem Cells

Biocompatible scaffolding materials play an important role in bone tissue engineering. This study sought to develop and characterize a nano-hydroxyapatite (nHA)/collagen I (ColI)/multi-walled carbon nanotube (MWCNT) composite scaffold loaded with recombinant bone morphogenetic protein-9 (BMP-9) for bone tissue engineering by in vitro and in vivo experiments. The composite nHA/ColI/MWCNT scaffolds were fabricated at various concentrations of MWCNTs (0.5, 1, and 1.5% wt) by blending and freeze drying. The porosity, swelling rate, water absorption rate, mechanical properties, and biocompatibility of scaffolds were measured. After loading with BMP-9, bone marrow mesenchymal stem cells (BMMSCs) were seeded to evaluate their characteristics in vitro and in a critical sized defect in Sprague-Dawley rats in vivo. It was shown that the 1% MWCNT group was the most suitable for bone tissue engineering. Our results demonstrated that scaffolds loaded with BMP-9 promoted differentiation of BMMSCs into osteoblasts in vitro and induced more bone formation in vivo. To conclude, nHA/ColI/MWCNT scaffolds loaded with BMP-9 possess high biocompatibility and osteogenesis and are a good candidate for use in bone tissue engineering.

Repair of critical sized cranial defects with BMP9-transduced calvarial cells delivered in a thermoresponsive scaffold

Large skeletal defects caused by trauma, congenital malformations, and post-oncologic resections of the calvarium present major challenges to the reconstructive surgeon. We previously identified BMP-9 as the most osteogenic BMP in vitro and in vivo. Here we sought to investigate the bone regenerative capacity of murine-derived calvarial mesenchymal progenitor cells (iCALs) transduced by BMP-9 in the context of healing critical-sized calvarial defects. To accomplish this, the transduced cells were delivered to the defect site within a thermoresponsive biodegradable scaffold consisting of poly(polyethylene glycol citrate-co-N-isopropylacrylamide mixed with gelatin (PPCN-g). A total of three treatment arms were evaluated: PPCN-g alone, PPCN-g seeded with iCALs expressing GFP, and PPCN-g seeded with iCALs expressing BMP-9. Defects treated only with PPCN-g scaffold did not statistically change in size when evaluated at eight weeks postoperatively (p = 0.72). Conversely, both animal groups treated with iCALs showed significant reductions in defect size after 12 weeks of follow-up (BMP9-treated: p = 0.0025; GFP-treated: p = 0.0042). However, H&E and trichrome staining revealed more complete osseointegration and mature bone formation only in the BMP9-treated group. These results suggest that BMP9-transduced iCALs seeded in a PPCN-g thermoresponsive scaffold is capable of inducing bone formation in vivo and is an effective means of creating tissue engineered bone for critical sized defects.