The prodomain of bone morphogenetic protein 2 promotes dimerization and cleavage of BMP6 homodimers and BMP2/6 heterodimers.

Bone morphogenetic protein 2 (BMP2) and BMP6 are key regulators of systemic iron homeostasis. All BMPs are generated as inactive precursor proteins that dimerize and are cleaved to generate the bioactive ligand and inactive prodomain fragments, but nothing is known about how BMP2 or BMP6 homodimeric or heterodimeric precursor proteins are proteolytically activated. Here, we conducted in vitro cleavage assays, which revealed that BMP2 is sequentially cleaved by furin at two sites, initially at a site upstream of the mature ligand, and then at a site adjacent to the ligand domain, while BMP6 is cleaved at a single furin motif. Cleavage of both sites of BMP2 is required to generate fully active BMP2 homodimers when expressed in Xenopus embryos or liver endothelial cells, and fully active BMP2/6 heterodimers in Xenopus. We analyzed BMP activity in Xenopus embryos expressing chimeric proteins consisting of the BMP2 prodomain and BMP6 ligand domain, or vice versa. We show that the prodomain of BMP2 is necessary and sufficient to generate active BMP6 homodimers and BMP2/6 heterodimers, whereas the BMP6 prodomain cannot generate active BMP2 homodimers or BMP2/6 heterodimers. We examined BMP2 and BMP6 homodimeric and heterodimeric ligands generated from native and chimeric precursor proteins expressed in Xenopus embryos. Whereas native BMP6 is not cleaved when expressed alone, it is cleaved to generate BMP2/6 heterodimers when co-expressed with BMP2. Furthermore, BMP2-6 chimeras are cleaved to generate BMP6 homodimers. Our findings reveal an important role for the BMP2 prodomain in dimerization and proteolytic activation of BMP6.

Key regulators of vascular calcification in chronic kidney disease: Hyperphosphatemia, BMP2, and RUNX2.

Vascular calcification is quite common in patients with end-stage chronic kidney disease and is a major trigger for cardiovascular complications in these patients. These complications significantly impact the survival rate and long-term prognosis of individuals with chronic kidney disease. Numerous studies have demonstrated that the development of vascular calcification involves various pathophysiological mechanisms, with the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) being of utmost importance. High phosphate levels, bone morphogenetic protein 2 (BMP2), and runt-related transcription factor 2 (RUNX2) play crucial roles in the osteogenic transdifferentiation process of VSMCs. This article primarily reviews the molecular mechanisms by which high phosphate, BMP2, and RUNX2 regulate vascular calcification secondary to chronic kidney disease, and discusses the complex interactions among these factors and their impact on the progression of vascular calcification. The insights provided here aim to offer new perspectives for future research on the phenotypic switching and osteogenic transdifferentiation of VSMCs, as well as to aid in optimizing clinical treatment strategies for this condition, bearing significant clinical and scientific implications.

Novel Strategies for Spatiotemporal and Controlled BMP-2 Delivery in Bone Tissue Engineering.

Bone morphogenetic protein-2 (BMP-2) has been commercially approved by the Food and Drug Administration for use in bone defects and diseases. BMP-2 promotes osteogenic differentiation of mesenchymal stem cells. In bone tissue engineering, BMP-2 incorporated into scaffolds can be used for stimulating bone regeneration in organoid construction, drug testing platforms, and bone transplants. However, the high dosage and uncontrollable release rate of BMP-2 challenge its clinical application, mainly due to the short circulation half-life of BMP-2, microbial contamination in bone extracellular matrix hydrogel, and the delivery method. Moreover, in clinical translation, the requirement of high doses of BMP-2 for efficacy poses challenges in cost and safety. Based on these, novel strategies should ensure that BMP-2 is delivered precisely to the desired location within the body, regulating the timing of BMP-2 release to coincide with the bone healing process, as well as release BMP-2 in a controlled manner to optimize its therapeutic effect and minimize side effects. This review highlights improvements in bone tissue engineering applying spatiotemporal and controlled BMP-2 delivery, including molecular engineering, biomaterial modification, and synergistic therapy, aiming to provide references for future research and clinical trials.

SCUBE3 promotes osteogenic differentiation and mitophagy in human bone marrow mesenchymal stem cells through the BMP2/TGF-ß signaling pathway.

In clinical settings, addressing large bone defects remains a significant challenge for orthopedic surgeons. The use of genetically modified bone marrow mesenchymal stem cells (BMSCs) has emerged as a highly promising approach for these treatments. Signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3) is a multifunctional secreted glycoprotein, the role of which remains unclear in human hBMSCs. This study used various experimental methods to elucidate the potential mechanism by which SCUBE3 influences osteogenic differentiation of hBMSCs in vitro. Additionally, the therapeutic efficacy of SCUBE3, in conjunction with porous GeLMA microspheres, was evaluated in vivo using a mouse bone defect model. Our findings indicate that SCUBE3 levels increase significantly during early osteogenic differentiation of hBMSCs, and that reducing SCUBE3 levels can hinder this differentiation. Overexpressing SCUBE3 elevated osteogenesis gene and protein levels and enhanced calcium deposition. Furthermore, treatment with recombinant human SCUBE3 (rhSCUBE3) protein boosted BMP2 and TGF-ß expression, activated mitophagy in hBMSCs, ameliorated oxidative stress, and restored osteogenic function through SMAD phosphorylation. In vivo, GELMA/OE treatment effectively accelerated bone healing in mice. In conclusion, SCUBE3 fosters osteogenic differentiation and mitophagy in hBMSCs by activating the BMP2/TGF-ß signaling pathway. When combined with engineered hydrogel cell therapy, it could offer valuable guidance for the clinical management of extensive bone defects.

Gunshot Injury With Bone Defect of the First Metatarsal Bone A Presentation of 2 Cases Treated With an Iliac Crest Structural Graft, Internal Fixation, and Bone Morphogenic Protein 2.

Gunshot injuries to the foot with segmental bone defects can be challenging to treat. When the vascularity is intact and the soft tissues allows, the goal should be to reconstruct the bony defect. We present 2 cases of a gunshot injury to the foot with a defect of the first metatarsal bone. Both cases were treated, with favorable outcome, with a structural iliac crest graft, internal fixation, and bone morphogenic protein 2.Level of Evidence: V, cases series, technical.

Site-specific bioorthogonal regulation of bone morphogenetic protein 2 expression for effective bone regeneration.

Growth factor holds great promise for bone regeneration, and spatiotemporal control of their expressing through site-specific reactions is crucial but challenging for on-demand therapy. In this study, we present the development of a novel unnatural amino acids (UAAs)-triggered therapeutic switch (UATS) system, composed of an orthogonal aminoacyl-tRNA-synthase (aaRS)-tRNA pair and a bone morphogenetic protein 2 (BMP2) gene harboring premature stop codon, which enable in situ and on-demand initiation of the expression of BMP2. The resulting UATS system allowed specifically control of base expressing on the BMP2 mRNA that switched to the BMP2 protein with complete structure and function to facilitate bone regeneration. Our investigations showed that the UATS system exhibits remarkable attributes of rapid, sensitive, reversible, and sustained BMP2 expression both in vitro and in vivo settings. Moreover, the implantation of microencapsulated cells with UATS system is applied to a mouse femur defect model, demonstrating high effciency in controlled expressing of BMP2 protein and substantial repair of bone defect following oral administration of UAAs. Therefore, our findings underscore the great potential of UATS system for on-demand awakening of functional growth factor, thus offering promising prospects in the realm of regenerative medicine.

BMP2 Binds Non-Specifically to PEG-Passivated Biomaterials and Induces pSMAD 1/5/9 Signalling.

Biomaterials are widely employed across diverse biomedical applications and represent an attractive strategy to explore how extracellular matrix components influence cellular response. In this study, the previously developed streptavidin platforms is aimed to use to investigate the role of glycosaminoglycans (GAGs) in bone morphogenetic protein 2 (BMP2) signaling. However, it is observed that the interpretation of findings is skewed due to the GAG-unrelated, non-specific binding of BMP2 on components of biomaterials. Non-specific adsorption of proteins is a recurrent and challenging issue for biomaterial studies. Despite the initial incorporation of anti-fouling polyethylene glycol (PEG) chains within biomaterials, the residual non-specific BMP2 adsorption still triggered BMP2 signaling within the same range as conditions of interest. The various options are explored to prevent BMP2 non-specific adsorption and a successful blocking condition involving a combination of bovine serum albumin and trehalose are identified. Furthermore, the effect of this blocking step improved when using gold platforms instead of glass, particularly with Chinese hamster ovary (CHO) cells. With this specific example, it is suggested that non-specific adsorption of BMPs on biomaterials may be a general concern - often undetected by classical surface-sensitive techniques - that needs to be addressed to better interpret cellular responses.

Dual-Functional Implant Based on Gellan-Xanthan Hydrogel with Diopside, BMP-2 and Lysostaphin for Bone Defect Repair and Control of Staphylococcal Infection.

A new dual-functional implant based on gellan-xanthan hydrogel with calcium-magnesium silicate ceramic diopside and recombinant lysostaphin and bone morphogenetic protein 2 (BMP-2)-ray is developed. In this composite, BMP-2 is immobilized on microparticles of diopside while lysostaphin is mixed directly into the hydrogel, providing sustained release of BMP-2 to allow gradual bone formation and rapid release of lysostaphin to eliminate infection immediately after implantation. Introduction of diopside of up to 3% (w/v) has a negligible effect on the mechanical properties of the hydrogel but provides a high sorption capacity for BMP-2. The hydrogels show good biocompatibility and antibacterial activity. Lysostaphin released from the implants over a 3 h period efficiently kills planktonic cells and completely destroys 24 h pre-formed biofilms of Staphylococcus aureus. Furthermore, in vivo experiments in a mouse model of critically-sized cranial defects infected with S. aureus show a complete lack of osteogenesis when implants contain only BMP-2, whereas, in the presence of lysostaphin, complete closure of the defect with newly formed mineralized bone tissue is observed. Thus, the new implantable gellan-xanthan hydrogel with diopside and recombinant lysostaphin and BMP-2 shows both osteogenic and antibacterial properties and represents a promising material for the treatment and/or prevention of osteomyelitis after bone trauma.

Long non-coding TRPM2-AS regulates fracture healing by targeting miR-545-3p/Bmp2.

OBJECTIVE: Delayed fracture healing increases the suffering of patients. An in-depth investigation of the pathogenesis of delayed fracture healing may offer new direction for the prevention and treatment. METHODS: The study included 63 normal healing tibial fractures and 58 delayed healing tibial fractures patients. Long non-coding RNA (lncRNA)TRPM2-AS, microRNA-545-3p (miR-545-3p), bone morphogenetic protein 2 (Bmp2) mRNA and osteogenic differentiation markers, including runt-related transcription factor 2 (Runx2), osteocalcin (Ocn), and alkaline phosphatase (Alp) mRNA expression were determined by Real-time quantitative reverse transcription-polymerase chain reaction in serum and MC3T3-E1 cells. The prediction potential of TRPM2-AS in delayed healing fracture patients was verified by receiver operating characteristic curves. The binding relationship of TRPM2-AS/miR-545-3p/Bmp2 was evaluated by dual luciferase reporter gene assay. Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry. RESULTS: TRPM2-AS was remarkably down-regulated in patients with delayed fracture healing and could better predict the fracture healing status. TRPM2-AS downregulation inhibited osteogenic markers mRNA expression, restrained proliferation, and promoted apoptosis of MC3T3-E1 cells (p < 0.05). In delayed fracture healing, miR-545-3p was dramatically up-regulated and was negatively regulated by TRPM2-AS. Reducing miR-545-3p eliminate the negative effect of TRPM2-AS down-regulation on osteoblast proliferation and differentiation (p < 0.05). miR-545-3p targets Bmp2, which plays a positive role in osteoblast differentiation (p < 0.05). CONCLUSION: This study found that TRPM2-AS has the potential to be a diagnostic marker for delayed fracture healing and revealed that the TRPM2-AS/miR-545-3p/Bmp2 axis affects fracture healing by regulating osteoblast.

Fabricating vascularized, anatomically accurate bone grafts using 3D bioprinted sectional bone modules, in-situ angiogenesis, BMP-2 controlled release, and bioassembly.

Bone grafting is the most common treatment for repairing bone defects. However, current bone grafting methods have several drawbacks. Bone tissue engineering emerges as a promising solution to these problems. An ideal engineered bone graft should exhibit high mechanical strength, osteogenic properties, and pre-vascularization. Both top-down (using bulk scaffold) and bottom-up (using granular modules) approaches face challenges in fulfilling these requirements. In this paper, we propose a novel sectional modular bone approach to construct osteogenic, pre-vascularized bone grafts in anatomical shapes. We 3D-printed a series of rigid, thin, sectional, porous scaffolds from a biodegradable polymer, tailored to the dimensions of a femur bone shaft. These thin sectional modules promote efficient nutrition and waste removal due to a shorter diffusion distance. The modules were pre-vascularized viain-situangiogenesis, achieved through endothelial cell sprouting from the scaffold struts. Angiogenesis was further enhanced through co-culture with bioprinted fibroblast microtissues, which secreted pre-angiogenic growth factors. Sectional modules were assembled around a porous rod incorporated with Bone Morphogenetic Protein-2 (BMP-2), which released over 3 weeks, demonstrating sustained osteogenic activity. The assembled scaffold, in the anatomical shape of a human femur shaft, was pre-vascularized, osteogenic, and possessed high mechanical strength, supporting 12 times the average body weight. The feasibility of implanting the assembled bone graft was demonstrated using a 3D-printed femur bone defect model. Our method provides a novel modular engineering approach for regenerating tissues that require high mechanical strength and vascularization.

A triple growth factor strategy for optimizing bone augmentation in mice.

With dental implant treatment becoming the gold standard, the need for effective bone augmentation prior to implantation has grown. This study aims to evaluate a bone augmentation strategy integrating three key growth factors: bone morphogenetic protein-2 (BMP-2), insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF). Collagen scaffolds incorporating BMP-2, IGF-1, or VEGF were fabricated and categorized into five groups based on their content: scaffold alone; BMP-2 alone (BMP-2); BMP-2 and IGF-1 (BI); BMP-2, IGF-1, and VEGF (BIV); and BMP-2 and IGF-1 with an earlier release of VEGF (BI + V). The prepared scaffolds were surgically implanted into the calvarias of C57BL/6JJcl mice, and hard tissue formation was assessed after 10 and 28 days through histological, tomographic, and biochemical analyses. The combination of BMP-2 and IGF-1 induced a greater volume of hard tissue augmentation compared with that of BMP-2 alone, regardless of VEGF supplementation, and these groups had increased levels of cartilage compared with others. The volume of hard tissue formation was greatest in the BIV group. In contrast, the BI + V group exhibited a hard tissue volume similar to that of the BI group. While VEGF and CD31 levels were highest in the BIV group at 10 days, there was no correlation at the same time point between hard tissue formation and the quantity of M2 macrophages. In conclusion, the simultaneous release of BMP-2, IGF-1, and VEGF proved to be effective in promoting bone augmentation.

Local FK506 delivery induces osteogenesis in rat bone defect and rabbit spine fusion models.

Bone grafting procedures are commonly used for the repair, regeneration, and fusion of bones in a wide range of orthopaedic surgeries, including large bone defects and spine fusion procedures. Autografts are the clinical gold standard, though recombinant human bone morphogenetic proteins (rhBMPs) are often used, particularly in difficult clinical situations. However, treatment with rhBMPs can have off-target effects and increase surgical costs, adding to patients' already high economic and mental burden. Recent studies have identified that FDA-approved immunosuppressant drug, FK506 (Tacrolimus), can also activate the BMP pathway by binding to its inhibitors. This study tested the hypothesis that FK506, as a standalone treatment, could induce osteogenic differentiation of human mesenchymal stromal cells (hMSCs), as well as functional bone formation in a rat segmental bone defect model and rabbit spinal fusion model. FK506 enhanced osteogenic differentiation and mineralization of hMSCs in vitro. Standalone treatment with FK506 delivered on a collagen sponge produced consistent bone bridging of a critically sized rat femoral defect with functional mechanical properties comparable to naïve bone. In a rabbit single level posterolateral spine fusion model, treatment with FK506 delivered on a collagen sponge successfully fused the L5-L6 vertebrae at rates comparable to rhBMP-2 treatment. These data demonstrate the ability of FK506 to induce bone formation in human cells and two challenging in vivo models, and indicate FK506 can be utilized to treat a variety of spine disorders.

BMP-Binding Polysulfonate Brushes to Control Growth Factor Presentation and Regulate Matrix Remodelling.

Bone morphogenetic proteins (BMPs) are important targets to incorporate in biomaterial scaffolds to orchestrate tissue repair. Glycosaminoglycans (GAGs) such as heparin allow the capture of BMPs and their retention at the surface of biomaterials at safe concentrations. Although heparin has strong affinities for BMP2 and BMP4, two important types of growth factors regulating bone and tissue repair, it remains difficult to embed stably at the surface of a broad range of biomaterials and degrades rapidly in vitro and in vivo. In this report, biomimetic poly(sulfopropyl methacrylate) (PSPMA) brushes are proposed as sulfated GAG mimetic interfaces for the stable capture of BMPs. The growth of PSPMA brushes via a surface-initiated activator regenerated by electron transfer polymerization is investigated via ellipsometry, prior to characterization of swelling and surface chemistry via X-ray photoelectron spectroscopy and Fourier transform infrared. The capacity of PSPMA brushes to bind BMP2 and BMP4 is then characterized via surface plasmon resonance. BMP2 is found to anchor particularly stably and at high density at the surface of PSPMA brushes, and a strong impact of the brush architecture on binding capacity is observed. These results are further confirmed using a quartz crystal microbalance with dissipation monitoring, providing some insights into the mode of adsorption of BMPs at the surface of PSPMA brushes. Primary adsorption of BMP2, with relatively little infiltration, is observed on thick dense brushes, implying that this growth factor should be accessible for further binding of corresponding cell membrane receptors. Finally, to demonstrate the impact of PSPMA brushes for BMP2 capture, dermal fibroblasts were then cultured at the surface of functionalized PSPMA brushes. The presence of BMP2 and the architecture of the brush are found to have a significant impact on matrix deposition at the corresponding interfaces. Therefore, PSPMA brushes emerge as attractive coatings for scaffold engineering and stable capture of BMP2 for regenerative medicine applications.

Bioactive coatings on 3D printed scaffolds for bone regeneration: Use of Laponite® to deliver BMP-2 in an ovine femoral condyle defect model.

Biomaterial-based approaches for bone regeneration seek to explore alternative strategies to repair non-healing fractures and critical-sized bone defects. Fracture non-union occurs due to a number of factors resulting in the formation of bone defects. Rigorous evaluation of the biomaterials in relevant models and assessment of their potential to translate towards clinical use is vital. Large animal experimentation can be used to model fracture non-union while scaling-up materials for clinical use. Growth factors modulate cell phenotype, behaviour and initiate signalling pathways leading to changes in matrix deposition and tissue formation. Bone morphogenetic protein-2 (BMP-2) is a potent osteogenic growth factor, with a rapid clearance time in vivo necessitating clinical use at a high dose, with potential deleterious side-effects. The current studies have examined the potential for Laponite® nanoclay coated poly(caprolactone) trimethacrylate (PCL-TMA900) scaffolds to bind BMP-2 for enhanced osteoinduction in a large animal critical-sized bone defect. An ovine femoral condyle defect model confirmed PCL-TMA900 scaffolds coated with Laponite®/BMP-2 produced significant bone formation compared to the uncoated PCL-TMA 900 scaffold in vivo, assessed by micro-computed tomography (µCT) and histology. This indicated the ability of Laponite® to deliver the bioactive BMP-2 on the PCL-TMA900 scaffold. Bone formed around the Laponite®/BMP-2 coated PCL-TMA900 scaffold, with no erroneous bone formation observed away from the scaffold material confirming localisation of BMP-2 delivery. The current studies demonstrate the ability of a nanoclay to localise and deliver bioactive BMP-2 within a tailored octet-truss scaffold for efficacious bone defect repair in a large animal model with significant implications for translation to the clinic.

Efficacy and safety of recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with autologous bone for the treatment of long bone nonunion: A report of a prospective case series.

INTRODUCTION: Recombinant human Bone morphogenetic proteins have been used for the treatment of nonunions with promising results. We have been investigating both experimentally and clinically the efficacy of the rhBMP-2 with the macro / micro-porous hydroxyapatite carrier granules on the potency on the reconstruction of long bone defect. The purpose of this study was to prospectively evaluate the efficacy and safety of this specific rhBMP-2 with HA carrier granules mixed with autologous cancellous bone in patients with nonunion and bone defect resulted from the fracture related infection. MATERIALS AND METHODS: This was a retrospective review of a prospective cohort at a university hospital. Patients diagnosed with nonunion under the definition of the United States Food and Drug Administration with bone defect after long bone fractures were enrolled from January 2020 to February 2021. We included patients with atrophic and oligotrophic nonunion, and hypertrophic nonunion with malalignment that needed to be corrected. The other patient group was consisted of segmental bone defect resulted from FRI. The maximum amount of rhBMP-2 allowed in this clinical study was 6 mg and was added to autologous bone at a 1:1 ratio. Autologous bone was added to the mixture if the volume of mixed graft was insufficient to fill the bone defect. Patients were followed 3, 6, and 12 months post-operatively. Each visit, a radiograph was taken for assessment. Visual analog scale (VAS), questionnaire for quality of life (SF-12 physical component summary [PCS], mental component summary [MCS]), and weight-bearing status were collected for functional outcome assessment. Drug safety was assessed by examining BMP-2 antibodies. RESULTS: Of the 24 enrolled patients (mean age: 57 years), 15 (62.5 %), 2 (8.33 %), and 7 (29.17 %) presented atrophic nonunion, hypertrophic nonunion with deformity, and bone defect after fracture related infection, respectively. Thirteen patients had nonunion in the femur, 9 in the tibia, and 1 in the humerus and radius. The average amount of harvested autologous bone was 9.25 g and 4.96 mg of rhBMP-2. All 24 patients achieved union after 1-year follow up. The union rate was 95.83 % and 100 % at 6 and 12 months postoperatively, respectively. Preoperative SF-12 PCS (mean: 34.71) improved at 6 and 12 months postoperatively, respectively. Preoperative SF-12 MCS (mean: 42.89) improved 12 months postoperatively (49.13, p = 0.0338). Change of VAS was statistically significant 3 months postoperatively (p = 0.0012). No adverse effects or development of BMP-2 antibodies were observed. CONCLUSION: BMP-2 combined with autogenous bone resulted in excellent radiographical and functional outcomes in a relatively small prospective series of patients with nonunion and bone defect, without adverse effects. Further investigations are necessary to support our finding and optimize treatment strategies in nonunion patients.

Dual release of daptomycin and BMP-2 from a composite of ß-TCP ceramic and ADA gelatin.

BACKGROUND: Antibiotic-containing carrier systems are one option that offers the advantage of releasing active ingredients over a longer period of time. In vitro sustained drug release from a carrier system consisting of microporous ß-TCP ceramic and alginate has been reported in previous works. Alginate dialdehyde (ADA) gelatin gel showed both better mechanical properties when loaded into a ß-TCP ceramic and higher biodegradability than pure alginate. METHODS: Dual release of daptomycin and BMP-2 was measured on days 1, 2, 3, 6, 9, 14, 21, and 28 by HPLC and ELISA. After release, the microbial efficacy of the daptomycin was verified and the biocompatibility of the composite was tested in cell culture. RESULTS: Daptomycin and the model compound FITC protein A (n = 30) were released from the composite over 28 days. A Daptomycin release above the minimum inhibitory concentration (MIC) by day 9 and a burst release of 71.7 ± 5.9% were observed in the loaded ceramics. Low concentrations of BMP-2 were released from the loaded ceramics over 28 days.

Inflow Tract Development.

The development of the inflow tract is undoubtedly one of the most complex remodeling events in the formation of the four-chambered heart. It involves the creation of two separate atrial chambers, the formation of an atrial/atrioventricular (AV) septal complex, the incorporation of the caval veins and coronary sinus into the right atrium, and the remodeling events that result in pulmonary venous return draining into the left atrium. In these processes, the atrioventricular mesenchymal complex, consisting of the major atrioventricular (AV) cushions, the mesenchymal cap on the primary atrial septum (pAS), and the dorsal mesenchymal protrusion (DMP), plays a crucial role.

Bone-targeted lipoplex-loaded three-dimensional bioprinting bilayer scaffold enhanced bone regeneration.

Clinical bone-morphogenetic protein 2 (BMP2) treatment for bone regeneration, often resulting in complications like soft tissue inflammation and ectopic ossification due to high dosages and non-specific delivery systems, necessitates research into improved biomaterials for better BMP2 stability and retention. To tackle this challenge, we introduced a groundbreaking bone-targeted, lipoplex-loaded, three-dimensional bioprinted bilayer scaffold, termed the polycaprolactone-bioink-nanoparticle (PBN) scaffold, aimed at boosting bone regeneration. We encapsulated BMP2 within the fibroin nanoparticle based lipoplex (Fibroplex) and functionalized it with DSS6 for bone tissue-specific targeting. 3D printing technology enables customized, porous PCL scaffolds for bone healing and soft tissue growth, with a two-step bioprinting process creating a cellular lattice structure and a bioink grid using gelatin-alginate hydrogel and DSS6-Fibroplex, shown to support effective nutrient exchange and cell growth at specific pore sizes. The PBN scaffold is predicted through in silico analysis to exhibit biased BMP2 release between bone and soft tissue, a finding validated by in vitro osteogenic differentiation assays. The PBN scaffold was evaluated for critical calvarial defects, focusing on sustained BMP2 delivery, prevention of soft tissue cell infiltration and controlled fiber membrane pore size in vivo. The PBN scaffold demonstrated a more than eight times longer BMP2 release time than that of the collagen sponge, promoting osteogenic differentiation and bone regeneration in a calvarial defect animal. Our findings suggest that the PBN scaffold enhanced the local concentration of BMP2 in bone defects through sustained release and improved the spatial arrangement of bone formation, thereby reducing the risk of heterotopic ossification.

Evaluation of Cardiospermum halicacabum on Bone Morphogenetic Protein-2 (BMP2) mRNA Expression in Osteoblast Cells.

Introduction Maintaining bone health is crucial for overall well-being, with osteoblasts playing a vital role in bone formation. Bone morphogenetic protein-2 (BMP2) is a key regulator, stimulating bone matrix synthesis and osteoblast differentiation. Recognizing BMP2's significance, there's growing interest in natural compounds, such as Cardiospermum halicacabum. This study explores Cardiospermum halicacabum's potential influence on BMP2 mRNA expression in osteoblast cells for insights into bone health modulation. Materials and methods  This research utilized Cardiospermum halicacabum to explore its impact on MG-63 cells, a human osteoblast cell line. Osteoblast cells were cultured in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% heat-inactivated fetal bovine serum, and maintained at 37°C in a 5% CO2 and 95% air environment. Cell viability was evaluated by seeding osteoblast cells into 96-well plates and exposing them to different concentrations of Cardiospermum halicacabum (2.0 µg/ml and 20 µg/ml). The study observed both the promotion of osteoblast cell growth in MG-63 and morphological changes in the cells under an inverted light microscope at 10x magnification. Results were presented using one-way analysis of variance (ANOVA) conducted with IBM SPSS Statistics for Windows, Version 23 (Released 2015; IBM Corp., Armonk, New York, United States). Result The reverse transcription-polymerase chain (RT-PCR) results revealed an increased expression of BMP-2 mRNA fold change in comparison to the control group. A clear positive correlation was observed between the BMP-2 mRNA fold change and the notable increase in the concentration of Cardiospermum halicacabum. This investigation revealed a direct association of BMP-2 mRNA expression with the proliferation of osteoblast cells. Specifically, the BMP-2 mRNA fold change was recorded at 2.26±1.05 in Cardiospermum halicacabum at 2.0 µg/ml and 2.0 ± 0.84 at 20 µg/ml, with corresponding significances of 0.00, respectively. Conclusion  Potential effects of Cardiospermum halicacabum on BMP-2 mRNA expression in osteoblast cells and its role in bone health modulation revealed that Cardiospermum halicacabum may upregulate BMP-2 mRNA expression, suggesting its potential as a natural compound for enhancing bone formation. The observed positive correlation between Cardiospermum halicacabum concentration and BMP-2 mRNA fold change showed the significance of this botanical agent in promoting osteoblast cell proliferation. These results highlight the importance of further research to explore the applications of Cardiospermum halicacabum in managing bone disorders and improving overall bone health.

Application of BMP-2 and its gene delivery vehicles in dentistry.

The restoration of bone defects resulting from tooth loss, periodontal disease, severe trauma, tumour resection and congenital malformations is a crucial task in dentistry and maxillofacial surgery. Growth factor- and gene-activated bone graft substitutes can be used instead of traditional materials to solve these problems. New materials will overcome the low efficacy and difficulties associated with the use of traditional bone substitutes in complex situations. One of the most well-studied active components for bone graft substitutes is bone morphogenetic protein-2 (BMP-2), which has strong osteoinductive properties. The aim of this review was to examine the use of BMP-2 protein and gene therapy for bone regeneration in the oral and maxillofacial region and to discuss its future use.