Bone Morphogenetic Protein-2 Treatment Research Articles

The effects of BMP2 and the mechanisms involved in the invasion and angiogenesis of IDH1 mutant glioma cells

PurposeThis study investigated the effect of an isocitrate dehydrogenase 1 (IDH1) mutation (mutIDH1) on the invasion and angiogenesis of human glioma cells.MethodsDoxycycline was used to induce the expression of mutIDH1 in glioma cells. Transwell and wound healing assays were conducted to assess glioma cell migration and invasion. Western blotting and cell immunofluorescence were used to measure the expression levels of various proteins. The influence of bone morphogenetic protein 2 (BMP2) on invasion, angiogenesis-related factors, BMP2-related receptor expression, and changes in Smad signaling pathway-related proteins were evaluated after treatment with BMP2. Differential gene expression and reference transcription analysis were performed.ResultsSuccessful infection with recombinant lentivirus expressing mutIDH1 was demonstrated. The IDH1 mutation promoted glioma cell migration and invasion while positively regulating the expression of vascularization-related factors and BMP2-related receptors. BMP2 exhibited a positive regulatory effect on the migration, invasion, and angiogenesis of mutIDH1-glioma cells, possibly mediated by BMP2-induced alterations in Smad signaling pathway-related factors.After BMP2 treatment, the differential genes of MutIDH1-glioma cells are closely related to the regulation of cell migration and cell adhesion, especially the regulation of Smad-related proteins. KEGG analysis confirmed that it was related to BMP signaling pathway and TGF-β signaling pathway and cell adhesion. Enrichment analysis of gene ontology and genome encyclopedia further confirmed the correlation of these pathways.ConclusionMutation of isocitrate dehydrogenase 1 promotes the migration, invasion, and angiogenesis of glioma cells, through its effects on the BMP2-driven Smad signaling pathway. In addition, BMP2 altered the transcriptional patterns of mutIDH1 glioma cells, enriching different gene loci in pathways associated with invasion, migration, and angiogenesis.

Potentiating effect of AMD3100 on bone morphogenetic protein-2 induced bone regeneration

BackgroundAMD3100, a CXCR4 antagonist, is currently prescribed for activating the mobilization of hematopoietic stem cells. Recently, AMD3100 was shown to potentiate bone morphogenetic protein-2 (BMP-2)-induced bone formation by stimulating the trafficking of mesenchymal cells. However, optimization of the strategic combination of AMD3100 and BMP-2 has not yet been clearly established. The purpose of this study was to evaluate the effect of AMD3100 on BMP-2-induced bone regeneration in vitro and in a mouse calvarial defect healing model.MethodsIn vitro osteoblastic differentiation and cell migration after sequential treatments with AMD3100 and BMP-2 were analyzed by alkaline phosphatase (ALP) activity, ALP staining, and calcium accumulation. Migration capacity was evaluated after treating mesenchymal cells with AMD3100 and/or BMP-2. A critical-size calvarial defect model was used to evaluate bone formation after sequential or continuous treatment with AMD3100 and BMP-2. The degree of bone formation in the defect was analyzed using micro-computed tomography (micro-CT) and histological staining.ResultsCompared with single treatment using either AMD3100 or BMP-2 alone, sequential treatment with AMD3100 followed by BMP-2 on mesenchymal cells increased osteogenic differentiation. Application of AMD3100 and subsequent BMP-2 significantly activated cell migration on mesenchymal cell than BMP-2 alone or AMD3100 alone.Micro-CT and histomorphometric analysis showed that continuous intraperitoneal (IP) injection of AMD3100 resulted significantly increased new bone formation in BMP-2 loaded scaffold in calvarial defect than control groups without AMD3100 IP injection. Additionally, both single IP injection of AMD3100 and subsequent BMP-2 injection to the scaffold in calvarial defect showed pronounced new bone formation compared to continuous BMP-2 treatment without AMD3100 treatment.ConclusionOur data suggest that single or continuous injection of AMD3100 can potentiate BMP-2-induced osteoblastic differentiation and bone regeneration. This strategic combination of AMD3100 and BMP-2 may be a promising therapy for bone regeneration.

Endometrial BMP2 Deficiency Impairs ITGB3-Mediated Trophoblast Invasion in Women With Repeated Implantation Failure.

Repeated implantation failure (RIF) leads to a waste of high-quality embryos and remains a challenge in assisted reproductive technology. During early human placentation, the invasion of trophoblast cells into the decidua is an essential step for the establishment of maternal-fetal interactions and subsequent successful pregnancy. Bone morphogenetic protein 2 (BMP2) has been reported to regulate endometrial receptivity and promote trophoblast invasion. However, whether there is dysregulation of endometrial BMP2 expression in patients with RIF remains unknown. Additionally, the molecular mechanisms underlying the effects of BMP2 on human trophoblast invasion and early placentation remain to be further elucidated. Midluteal phase endometrial samples were biopsied from patients with RIF and from routine control in vitro fertilization followed by quantitative polymerase chain reaction and immunoblotting analyses. Human trophoblast organoids, primary human trophoblast cells, and an immortalized trophoblast cell line (HTR8/SVneo) were used as study models. We found that BMP2 was aberrantly low in midluteal phase endometrial tissues from patients with RIF. Recombinant human BMP2 treatment upregulated integrin β3 (ITGB3) in a SMAD2/3-SMAD4 signaling-dependent manner in both HTR8/SVneo cells and primary trophoblast cells. siRNA-mediated integrin β3 downregulation reduced both basal and BMP2-upregulated trophoblast invasion and vascular mimicry in HTR8/SVneo cells. Importantly, shRNA-mediated ITGB3 knockdown significantly decreased the formation ability of human trophoblast organoids. Our results demonstrate endometrial BMP2 deficiency in patients with RIF. ITGB3 mediates both basal and BMP2-promoted human trophoblast invasion and is essential for early placentation. These findings broaden our knowledge regarding the regulation of early placentation and provide candidate diagnostic and therapeutic targets for RIF clinical management.

SAT662 Bone Morphogenetic Protein 7 Induces Transdifferentiation Of Human White Preadipocytes Into Thermogenic Beige Adipocytes

Abstract Disclosure: S.L. Ali: None. J. Katz: None. A.M. Cypess: None. Chronic treatment of women with mirabegron, which activates the β3-adrenergic receptor, increases the mass and energy expenditure of thermogenic adipocytes and leads to metabolic benefits including improvement of glucose and lipid homeostasis. In humans, thermogenic adipose tissue is composed of brown and beige/brite (from “brown-in-white”) cells that have different lineages and potentially different functions. Beige cells are of therapeutic interest because they are derived from white adipose tissue, which is present at a considerably higher volume compared to brown adipose tissue. Identifying processes that can transdifferentiate white into beige cells could lead to treatments for obesity-related metabolic disease. We hypothesized that short-term treatment with bone morphogenetic protein 7 (BMP7), a member of the transforming growth factor-β (TGF-β) family of cell regulatory proteins, prior to differentiation could be sufficient to induce white to beige transition in human white preadipocytes. We established paired clonal immortalized human white and brown preadipocyte lines and differentiated the white adipocytes ± BMP7 (3.3 nM) for 7 days prior to differentiation. Cells were collected at d0 (undifferentiated) and d30 (fully mature adipocytes) for gene expression analyses. Short-term exposure to BMP7 in white preadipocytes significantly decreased the expression of white-specific markers TCF21 and HOXC8. The beige-specific markers TBX1 and TMEM26, and the thermogenic marker UCP1 were significantly higher in BMP7-treated white adipocytes. However, long term, 30-day exposure to BMP7 treatment reversed the thermogenic transdifferentiation both human white and brown adipocytes. Basal and drug-induced maximal respiration measured via Seahorse XFe96 Analyzer were significantly higher in short-term BMP7-treated white adipocytes. Our data indicate that BMP7 is capable of transdifferentiating human white preadipocytes into thermogenic beige adipocytes. Given that extended treatment reduced the impact of BMP7 indicates that precise timing of interventions will be needed to utilize white-to-beige transdifferentiation to treat obesity-associated metabolic disease. Presentation: Saturday, June 17, 2023

PTEN-AKT pathway attenuates apoptosis and adverse remodeling in ponatinib-induced skeletal muscle toxicity following BMP-7 treatment.

Tyrosine kinase inhibitors (TKIs) including ponatinib are commonly used to treat cancer patients. Unfortunately, TKIs induce cardiac as well as skeletal muscle dysfunction as a side effect. Therefore, detailed mechanistic studies are required to understand its pathogenesis and to develop a therapeutic treatment. The current study was undertaken to examine whether ponatinib induces apoptosis and apoptotic mechanisms both in vitro and in vivo models and furthermore to test the potential of bone morphogenetic protein 7 (BMP-7) as a possible treatment option for its attenuation. Sol8 cells, a mouse myogenic cell line was exposed to ponatinib to generate an apoptotic cell culture model and were subsequently treated with BMP-7 to understand its protective effects. For the in vivo model, C57BL/6J mice were administered with ponatinib to understand apoptosis, cell signaling apoptotic mechanisms, and adverse muscle remodeling and its attenuation with BMP-7. TUNEL staining, immunohistochemistry (IHC), and real-time polymerase chain reaction (RT-PCR) methods were used. Our data show significantly (p < 0.05) increased TUNEL staining, caspase-3, BAX/Bcl2 ratio in the in vitro model. Furthermore, our in vivo muscle data show ponatinib-induced muscle myopathy, and loss in muscle function. The observed muscle myopathy was associated with increased apoptosis, caspase-3 staining, and BAX/Bcl-2 ratio as confirmed with IHC and RT-PCR. Furthermore, our data show a significant (p < 0.05) increase in the involvement of cell signaling apoptotic regulator protein PTEN and a decrease in cell survival protein AKT. These results suggest that increased apoptosis following ponatinib treatment showed an increase in skeletal muscle remodeling, sarcopenia, and fibrosis. Furthermore, BMP-7 treatment significantly (p < 0.05) attenuated ponatinib-induced apoptosis, BAX/Bcl2 ratio, decreased PTEN, and increased cell survival protein AKT, decreased adverse muscle remodeling, and improved muscle function. Overall, we provide evidence that ponatinib-induces apoptosis leading to sarcopenia and muscle myopathy with decreased function which was attenuated by BMP-7.

P9. Sex differences in response to recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rat posterolateral fusion spine model

<h3>BACKGROUND CONTEXT</h3> Estrogen modulates bone activity largely through inhibition of osteoclast bone resorption and bone morphogenetic protein-2 (BMP-2) signaling pathways in osteoblasts. Minimal data exist concerning potential sex-dependent differences in BMP-2-mediated bone regeneration. Here, we aimed to quantify sex-dependent differences in the bone healing response to recombinant human BMP-2 (rhBMP-2) treatment in a rat posterolateral spinal fusion model. <h3>METHODS</h3> A total of 48 female and male Sprague-Dawley rats (N=24/group), underwent L4-L5 posterolateral fusion with bilateral placement of absorbable collagen sponges, loaded with 5 µg of rhBMP-2 (10 µg/animal). At 8 weeks postoperatively, 10 specimens of each sex were tested in flexion-extension with quantification of range of motion (ROM) and stiffness. The remaining specimens were evaluated for new bone growth and fusion via radiography, blinded manual palpation and microcomputed tomography (microCT). Laboratory microCT quantified bone microarchitecture and synchrotron microCT examined bone microstructure. On histology, the number of adipocytes within a standardized field of view was counted for both male and female fusion masses. <h3>RESULTS</h3> Manual palpation scores differed significantly between sexes, with mean fusion scores of 2.4±0.4 in females vs 3.1±0.6 in males, p < 0.001. Biomechanical stiffness did not differ between sexes, but ROM was significantly greater and more variable for females vs males (3.7°±5.6° vs 0.27°±0.15°,p < 0.005, respectively. Laboratory microCT showed significantly smaller volumes of fusion masses in females vs males (262±87 mm³ vs 732±238 mm³, respectively, p < 0.001) but significantly higher bone volume fraction (0.27±0.08 vs 0.12±0.05, respectively, p < 0.001). Mean trabecular thickness was not different, but trabecular number was significantly greater in females (3.1±0.5 mm-1vs 1.5±0.4 mm-1, respectively, p<0.001). Synchrotron microCT showed fine bone structures developing in both sexes at the 8-week time point. Adipocyte density was found to be significantly higher in male fusion masses than in female fusion masses. <h3>CONCLUSIONS</h3> This study demonstrates that sex-based factors may influence both the quantity and quality of bone formation in patients receiving rhBMP-2 for a variety of orthopedic applications. We found that male rats had significantly higher fusion scores, greater fusion-mass volume, and lower ratio of new bone volume to total volume compared to female rats. Male and female mean trabecular thicknesses were equal, but the female fusion masses were more densely filled with trabeculae (higher trabecular number) than those of males. MicroCT results suggested that the male trabeculae were more rod-like and the female more plate-like, although the methods that were used are generally considered less accurate for trabecular bone, which has a high degree of concavity. The incomplete fusions on three female rats, evidenced by high ROM and small gaps on microCT, suggest that females may have a more variable response to rhBMP-2. Investigation into whether these sex-based differences are specific to rhBMP-2-induced bone formation or are more general to bone regeneration/healing is prudent. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Systemic effects of BMP2 treatment of fractures on non-injured skeletal sites during spaceflight.

Unloading associated with spaceflight results in bone loss and increased fracture risk. Bone morphogenetic protein 2 (BMP2) is known to enhance bone formation, in part, through molecular pathways associated with mechanical loading; however, the effects of BMP2 during spaceflight remain unclear. Here, we investigated the systemic effects of BMP2 on mice sustaining a femoral fracture followed by housing in spaceflight (International Space Station or ISS) or on Earth. We hypothesized that in spaceflight, the systemic effects of BMP2 on weight-bearing bones would be blunted compared to that observed on Earth. Nine-week-old male mice were divided into four groups: 1) Saline+Earth; 2) BMP+Earth; 3) Saline+ISS; and 4) BMP+ISS (n = 10 mice/group, but only n = 5 mice/group were reserved for micro-computed tomography analyses). All mice underwent femoral defect surgery and were followed for approximately 4 weeks. We found a significant reduction in trabecular separation within the lumbar vertebrae after administering BMP2 at the fracture site of mice housed on Earth. In contrast, BMP2 treatment led to a significant increase in trabecular separation concomitant with a reduction in trabecular number within spaceflown tibiae. Although these and other lines of evidence support our hypothesis, the small sample size associated with rodent spaceflight studies limits interpretations. That said, it appears that a locally applied single dose of BMP2 at the femoral fracture site can have a systemic impact on distant bones, affecting bone quantity in several skeletal sites. Moreover, our results suggest that BMP2 treatment works through a pathway involving mechanical loading in which the best outcomes during its treatment on Earth occurred in the weight-bearing bones and in spaceflight occurred in bones subjected to higher muscle contraction.

Poster 107: The Use of Coacervate Sustained Release System to Identify the Most Potent BMP for Bone Regeneration

Poster 107: The Use of Coacervate Sustained Release System to Identify the Most Potent BMP for Bone Regeneration

Therapeutic Benefit in Rheumatoid Cachexia Illustrated Using a Novel Primary Human Triple Cell Coculture Model.

Background The loss of muscle mass in rheumatoid arthritis (RA), termed rheumatoid cachexia, is predicted to result from the complex interactions between different cell types involved in the maintenance of skeletal muscle mass, namely, myoblasts, fibroblasts, and macrophages. The complexity within the muscle is further highlighted by the incidence of nonresponsiveness to current RA treatment strategies. Method This study aimed at determining differences in the cellular responses in a novel human primary cell triple coculture model exposed to serum collected from nonarthritic controls (NC), RA treatment naïve (RATN), and RA treatment-nonresponding (RATNR) patients. Bone morphogenetic protein-7 (BMP-7) was investigated as a treatment option. Results Plasma analysis indicated that samples were indeed representative of healthy and RA patients—notably, the RATNR patients additionally exhibited dysregulated IL-6/IL-10 correlations. Coculture exposure to serum from RATNR patients demonstrated increased cellular growth (p < 0.001), while both hepatocyte growth factor (p < 0.01) and follistatin (p < 0.001) were reduced when compared to NC. Furthermore, decreased concentration of markers of extracellular matrix formation, transforming growth factor-β (TGF-β; p < 0.05) and fibronectin (p < 0.001), but increased collagen IV (p < 0.01) was observed following RATNR serum exposure. Under healthy conditions, BMP-7 exhibited potentially beneficial results in reducing fibrosis-generating TGF-β (p < 0.05) and fibronectin (p < 0.05). BMP-7 further exhibited protective potential in the RA groups through reversing the aberrant tendencies observed especially in the RATNR serum-exposed group. Conclusion Exposure of the triple coculture to RATN and RATNR serum resulted in dysregulated myoblast proliferation and growth, and ECM impairment, which was reversed by BMP-7 treatment.

Bone morphogenetic protein 2- and estradiol-17β-induced changes in ovarian transcriptome during primordial follicle formation†.

Estradiol-17β has been shown to promote primordial follicle formation and to involve bone morphogenetic protein 2 (BMP2) as a downstream effector to promote primordial follicle in hamsters. However, the molecular mechanism whereby these factors regulate ovarian somatic cells to pre-granulosa cells transition leading to primordial follicle formation remains unclear. The objective of this study was to determine whether BMP2 and/or estradiol-17β would regulate the expression of specific ovarian transcriptome during pre-granulosa cells transition and primordial follicle formation in the mouse ovary. BMP2 mRNA level increased during the period of primordial follicle formation with the concurrent presence of BMP2 protein in ovarian somatic cells. Estradiol-17β but not BMP2 exposure led to increased expression of ovarian BMP2 messenger RNA (mRNA), and the effect of estradiol-17β could not be suppressed by 4-[6-[4-(1-Piperazinyl)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]quinoline dihydrochloride (LDN) 193189. BMP2 or estradiol-17β stimulated primordial follicle formation without inducing apoptosis. Ribonucleic acid-sequence analysis (RNA-seq) of ovaries exposed to exogenous BMP2 or estradiol-17β revealed differential expression of several thousand genes. Most of the differentially expressed genes, which were common between BMP2 or estradiol-17β treatment demonstrated concordant changes, suggesting that estradiol-17β and BMP2 affected the same set of genes during primordial follicle formation. Further, we have identified that estradiol-17β, in cooperation with BMP2, could affect the expression of three major transcription factors, GATA binding protein 2, GATA binding protein 4 and Early growth response 2, and one serine protease, hepsin, in pre-granulosa cells during primordial follicle formation. Taken together, results of this study suggest that estradiol-17β and BMP2 may regulate ovarian gene expression that promote somatic cells to pre-granulosa cells transition and primordial follicle formation in the mouse ovary.

Induction of human trophoblast stem-like cells from primed pluripotent stem cells

The placenta is a transient but important multifunctional organ crucial for healthy pregnancy for both mother and fetus. Nevertheless, limited access to human placenta samples and the paucity of a proper in vitro model system have hampered our understanding of the mechanisms underlying early human placental development and placenta-associated pregnancy complications. To overcome these constraints, we established a simple procedure with a short-term treatment of bone morphogenetic protein 4 (BMP4) in trophoblast stem cell culture medium (TSCM) to convert human primed pluripotent stem cells (PSCs) to trophoblast stem-like cells (TSLCs). These TSLCs show not only morphology and global gene expression profiles comparable to bona fide human trophoblast stem cells (TSCs) but also long-term self-renewal capacity with bipotency that allows the cells to differentiate into functional extravillous trophoblasts (EVT) and syncytiotrophoblasts (ST). These indicate that TSLCs are equivalent to genuine human TSCs. Our data suggest a straightforward approach to make human TSCs directly from preexisting primed PSCs and provide a valuable opportunity to study human placenta development and pathology from patients with placenta-related diseases.

Connective tissue growth factor mediates bone morphogenetic protein 2-induced increase in hyaluronan production in luteinized human granulosa cells

BackgroundHyaluronan is the main component of the cumulus-oocyte complex (COC) matrix, and it maintains the basic structure of the COC during ovulation. As a member of the transforming growth factor β (TGF-β) superfamily, bone morphogenetic protein 2 (BMP2) has been identified as a critical regulator of mammalian folliculogenesis and ovulation. However, whether BMP2 can regulate the production of hyaluronan in human granulosa cells has never been elucidated.MethodsIn the present study, we investigated the effect of BMP2 on the production of hyaluronan and the underlying molecular mechanism using both immortalized (SVOG) and primary human granulosa-lutein (hGL) cells. The expression of three hyaluronan synthases (including HAS1, HAS2 and HAS3) were examined following cell incubation with BMP2 at different concentrations. The concentrations of the hyaluronan cell culture medium were determined by enzyme-linked immunosorbent assay (ELISA). The TGF-β type I receptor inhibitors (dorsomorphin and DMH-1) and small interfering RNAs targeting ALK2, ALK3, ALK6 and SMAD4 were used to investigate the involvement of TGF-β type I receptor and SMAD-dependent pathway.ResultsOur results showed that BMP2 treatment significantly increased the production of hyaluronan by upregulating the expression of hyaluronan synthase 2 (HAS2). In addition, BMP2 upregulates the expression of connective tissue growth factor (CTGF), which subsequently mediates the BMP2-induced increases in HAS2 expression and hyaluronan production because overexpression of CTGF enhances, whereas knockdown of CTGF reverses, these effects. Notably, using kinase inhibitor- and siRNA-mediated knockdown approaches, we demonstrated that the inductive effect of BMP2 on the upregulation of CTGF is mediated by the ALK2/ALK3-mediated SMAD-dependent signaling pathway.ConclusionsOur findings provide new insight into the molecular mechanism by which BMP2 promotes the production of hyaluronan in human granulosa cells.

An Audit of the effect of Bone Morphogenetic Protein-2 Treatment in patients with non-union of long bone fractures.

To evaluate the outcomes, clinical and radiological application of Bone Morphogenetic Protein-2 alone versus Bone Morphogenetic Protein-2 with autograft in long bone non-unions. A prospective review of patients was done with fracture non-union admitted to Aga Khan University Hospital, Karachi, from January 2016 to January 2019. The patients were divided into two groups; those exposed to Bone Morphogenetic Protein-2 alone in group 1, and those exposed to Bone Morphogenetic Protein-2 plus autologous graft in group 2. Background characteristics of both the groups were analysed. Patients were followed up at 6, 12 and 24 weeks through their medical records. The primary outcome was postoperative union at 6, 12 and 24. Union was defined by having the clinical union as well as the radiological union at the same time of assessment. Of the 80 patients enrolled, 13(16.25%) were excluded, and 5(6.25%) were lost to follow-up. The final sample had 62(77.5%) patients; 35(56.5%) in group 1, and 27(43.5%) in group 2. Union at 6 weeks was observed in 13(21%) patients; 8(62%) in group 1, and 5(38%) in group 2. Union at 12 weeks was observed in 38(61%) patients; 20(53%) in group 1, and 18(47%) in group 2. Results showed that using the adjuvant treatment alone was not worse than using it along with bone autologous graft.

Effects of Signaling Activation of Bone Morphogenetic Protein 2 on the Differentiation and Infiltration of Regulatory T Lymphocytes in Tumors

Objective To determine whether the signaling activation of bone morphogenetic protein 2(BMP2)can induce myeloid-derived suppressor cells(MDSC)to secret transforming growth factor β(TGF-β),further enhancing the differentiation and infiltration of regulatory T lymphocytes(Treg)into tumor tissue. Methods The BMP2-induced mRNA and protein expression of TGF-β in MDSC was detected by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay(ELISA),respectively.The effect of BMP2-induced TGF-β secretion by MDSC on Treg differentiation was then determined by flow cytometry.Finally,we implanted the recombined human bone morphogenetic protein 2(rhBMP2)collagen gels into tumor-burdened mice to examine the role of BMP2 in Treg differentiation via MDSC-secreted TGF-β in vivo.The protein levels of TGF-β in peripheral blood and tumor tissue were detected by ELISA,and the infiltration of Treg cells in tumor tissue was detected by immunofluorescence assay. Results BMP2 up-regulated the mRNA and protein levels of TGF-β in MDSC in vitro.TGF-β secreted by the MDSC exposed to BMP2 treatment could induce the differentiation of Treg cells in vitro.Local implantation of rhBMP2 could increase the level of TGF-β protein in peripheral blood and tumor tissue of mice,further enhancing the infiltration of Treg cells into tumors. Conclusion BMP2 signaling activation can induce the differentiation of Treg cells by promoting the secretion of TGF-β in MDSC,and subsequently promote the infiltration of Treg cells into tumors.

Efficacy of apolipoprotein 2-Jifusheng in the treatment of osteomyelitis in rabbits

To evaluate the effect of one-stage treatment of bone morphogenetic protein 2 combined with Jifusheng in the experimental model of osteomyelitis in rabbits. The model of chronic osteomyelitis of tibia was established in 30 3-month-old male New Zealand white rabbits with a body weight of (2.0±0.5) kg, and the model was verified 4 weeks after operation. Thirty rabbits with osteomyelitis were randomly divided into 3 groups with 10 rabbits in each group (n= 10). The model group did not do any treatment after focal debridement, treatment group A was implanted with musculosheng at the site of focal debridement and bone defect, and treatment group B was implanted with apolipoprotein 2-Jifusheng at the site of focal debridement and bone defect. The therapeuticeffect was evaluated by blood biochemical, microbiological, imaging, pathological and immunohistochemical examination 8 weeks after operation. At 4 weeks after operation, 30 rabbits with osteomyelitis were successfully validated. The results of serological examination showed that the hypersensitive C-reactive protein (CRP) and white blood cell count(WBC)in the model group were significantly higher than those in the blank group at 2 and 4 weeks after operation. Eight weeks after treatment, the detection of blood indexes showed that the white blood cell count (WBC)and hypersensitive C reactive protein (CRP)in treatment group A and treatment group B were significantly lower than those in the model group (P<0.05), but there was no significant difference between treatment group An and treatment group B (P>0.05). Eight weeks after treatment, the bone defect area was measured. The bone volume/total volume (BV/TV) and bone mineral density (BMD)in treatment group A and B were significantly higher than those in the model group (P<0.05), and the bone volume/total volume (BV/TV) and bone mineral density(BMD)in treatment group B were significantly higher than those in treatment group A (P<0.05), the repair of bone defect was almost complete, and the bone volume and bone mineral density increased significantly. At 8 weeks after treatment, the number of osteoblasts/bone tissue area (N.Ob/T.Ar) and the number of osteoblasts/bone tissue perimeter (N.Ob/B.Pm) in treatment group A and B were significantly higher than those in model group, and the N.Ob/T.Ar and N.Ob/B.Pm in treatment group B were significantly higher than those in treatment group A. The immunohistochemical staining of TNF- α and IL-6 around bone tissue in treatment group A and treatment group B was significantly less than that in model group, but there was no significant difference between treatment group B and treatment group A. The combined application of apolipoprotein 2-Jifusheng can promote bone repair and reduce the inflammation of the focus. it can treat rabbits with osteomyelitis in one stage, provide objective basis for the formulation of clinical treatment strategy of osteomyelitis and further promote clinical research.

BMP-7 Attenuates Inflammation-Induced Pyroptosis and Improves Cardiac Repair in Diabetic Cardiomyopathy.

In the present study, we investigated a novel signaling target in diabetic cardiomyopathy where inflammation induces caspase-1-dependent cell death, pyroptosis, involving Nek7-GBP5 activators to activate the NLRP3 inflammasome, destabilizes cardiac structure and neovascularization. Furthermore, we explored the therapeutic ability of bone morphogenetic protein-7 (BMP-7) to attenuate these adverse effects. C57BL/6J mice (n = 16 mice/group) were divided into: control (200 mg/kg, 0.9% saline intraperitoneal injection, i.p.); Streptozotocin (STZ) and STZ-BMP-7 groups (STZ, 200 mg/kg, i.p. injection). After 6 weeks, heart function was examined with echocardiography, and mice were sacrificed. Immunostaining, Western blotting, H&E, and Masson’s trichrome staining was performed on heart tissues. STZ-induced diabetic cardiomyopathy significantly increased inflammasome formation (TLR4, NLRP3, Nek7, and GBP5), pyroptosis markers (caspase-1, IL-1β, and IL-18), inflammatory cytokines (IL-6 and TNF-α), MMP9, and infiltration of monocytes (CD14), macrophage (iNOS), and dendritic cells (CD11b and CD11c) (p < 0.05). Moreover, a significant endothelial progenitor cells (EPCs) dysfunction (c-Kit/FLk-1, CD31), adverse cardiac remodeling, and reduction in left ventricular (LV) heart function were observed in STZ versus control (p < 0.05). Treatment with BMP-7 significantly reduced inflammasome formation, pyroptosis, and inflammatory cytokines and infiltrated inflammatory cells. In addition, BMP-7 treatment enhanced EPC markers and neovascularization and subsequently improved cardiac remodeling in a diabetic heart. Moreover, a significant improvement in LV heart function was achieved after BMP-7 administration relative to diabetic mice (p < 0.05). In conclusion, BMP-7 attenuated inflammation-induced pyroptosis, adverse cardiac remodeling, and improved heart function via the TLR4-NLRP3 inflammasome complex activated by novel signaling Nek7/GBP5. Our BMP-7 pre-clinical studies of mice could have significant potential as a future therapy for diabetic patients.

Human Peripheral Nerve-Derived Pluripotent Cells Can Be Stimulated by In Vitro Bone Morphogenetic Protein-2.

We have recently identified a population of cells within the peripheral nerves of adult rodent animals (mice and rats) that can respond to Bone Morphogenetic Protein-2 (BMP-2) exposure or physical injury to rapidly proliferate. More importantly, these cells exhibited embryonic differentiation potentials that could be induced into osteoblastic and endothelial cells in vitro. The current study examined human nerve specimens to compare and characterize the cells after BMP-2 stimulation. Fresh pieces of human nerve tissue were minced and treated with either BMP-2 (750 ng/mL) or a PBS vehicle for 12 h at 37 °C, before being digested in 0.2% collagenase and 0.05% trypsin-EDTA. Isolated cells were cultured in a restrictive stem cell medium. Significantly more cells were obtained from the nerve pieces with the BMP-2 treatment in comparison with the PBS vehicle controls. Cell colonies started to form at Day 3. Expressions of the four transcription factors, namely, Klf4, c-Myc, Sox2, and Oct4, were confirmed at both the transcriptional and translational levels. The cells can be maintained in the stem cell culture medium for at least 6 weeks without changing their morphology. When the cells were transferred to a fibroblast growth medium, dispersed spindle-shaped motile cells were noted and became fibroblast activated protein-α (FAP) positive with immunocytochemistry staining. The data suggest that human peripheral nerve tissue also contains a population of cells that can respond to BMP-2 and express Klf4, Sox2, cMyc, and Oct4—the four transcription factors driving cell pluripotency. These cells are able to differentiate into FAP-positive fibroblasts. In summary, in human peripheral nerves also reside a population of quiescent cells with pluripotency potential that may be the same cells as rodent nerve-derived adult stem (NEDAPS) cells. It is proposed that these cells are possibly at the core of a previously unknown natural mechanism for healing an injury.

Role of BMP signaling during early development of the annelid Capitella teleta

The mechanisms regulating nervous system development are still unknown for a wide variety of taxa. In insects and vertebrates, bone morphogenetic protein (BMP) signaling plays a key role in establishing the dorsal-ventral (D-V) axis and limiting the neuroectoderm to one side of that axis, leading to speculation about the conserved evolution of centralized nervous systems. Studies outside of insects and vertebrates show a more diverse picture of what, if any role, BMP signaling plays in neural development across Bilateria. This is especially true in the morphologically diverse Spiralia (≈Lophotrochozoa). Despite several studies of D-V axis formation and neural induction in spiralians, there is no consensus for how these two processes are related, or whether BMP signaling may have played an ancestral role in either process. To determine the function of BMP signaling during early development of the spiralian annelid Capitella teleta, we incubated embryos and larvae in BMP4 protein for different amounts of time. Adding exogenous BMP protein to early-cleaving C. teleta embryos had a striking effect on formation of the brain, eyes, foregut, and ventral midline in a time-dependent manner. However, adding BMP did not block brain or VNC formation or majorly disrupt the D-V axis. We identified three key time windows of BMP activity. 1) BMP treatment around birth of the 3rd-quartet micromeres caused the loss of the eyes, radialization of the brain, and a reduction of the foregut, which we interpret as a loss of A- and C-quadrant identities with a possible trans-fate switch to a D-quadrant identity. 2) Treatment after the birth of micromere 4d induced formation of a third ectopic brain lobe, eye, and foregut lobe, which we interpret as a trans-fate switch of B-quadrant micromeres to a C-quadrant identity. 3) Continuous BMP treatment from late cleavage (4d ​+ ​12 ​h) through mid-larval stages resulted in a modest expansion of Ct-chrdl expression in the dorsal ectoderm and a concomitant loss of the ventral midline (neurotroch ciliary band). Loss of the ventral midline was accompanied by a collapse of the bilaterally-symmetric ventral nerve cord, although the total amount of neural tissue was not greatly affected. Our results compared with those from other annelids and molluscs suggest that BMP signaling was not ancestrally involved in delimiting neural tissue to one region of the D-V axis. However, the effects of ectopic BMP on quadrant-identity during cleavage stages may represent a non-axial organizing signal that was present in the last common ancestor of annelids and mollusks. Furthermore, in the last common ancestor of annelids, BMP signaling may have functioned in patterning ectodermal fates along the D-V axis in the trunk. Ultimately, studies on a wider range of spiralian taxa are needed to determine the role of BMP signaling during neural induction and neural patterning in the last common ancestor of this group. Ultimately, these comparisons will give us insight into the evolutionary origins of centralized nervous systems and body plans.

BMP6 Mediates BMP2-Increased Human Trophoblast Invasion

TGF-β superfamily proteins play divergent roles in regulating human extravillous trophoblast (EVT) invasion and their coordinated effects are essential for adequate placentation during pregnancy 1. Bone morphogenetic protein 2 (BMP2), which belongs to the BMP subfamily of TGF-β superfamily, has been shown to promote human EVT invasion and the acquisition of endothelial-like phenotype 2,3. It has been reported that BMP2 promotes EVT invasion by up-regulating Activin A, a growth factor which also belongs to TGF-β superfamily. However, whether BMP6 mediates the pro-invasive effect of BMP2 has yet to be determined. Herein, we firstly treated immortalized trophoblast cells (HTR8/SVneo) with recombinant BMP2 protein for 6 and 24 hrs, and our bulk-RNA sequencing results demonstrated significantly increased BMP6 mRNA levels after BMP2 treatment. Furthermore, we confirmed the up-regulatory effects of BMP2 on BMP6 mRNA and protein levels in both HTR8/SVneo and primary EVTs isolated from first-trimester villi. Notably, siRNA-mediated down-regulation of BMP6 significantly attenuated both basal and BMP2-induced cell invasion in HTR8/SVneo cells as measured by Matrigel-coated transwell invasion assay. In summary, our results firstly demonstrated the up-regulatory effect of BMP2 on BMP6 expression in human trophoblasts and identified the mediation role of BMP6 in BMP2-promoted EVT invasion, suggesting the interplay between BMP subfamily members during EVT invasion regulation. Our ongoing research focusing the underlying molecular mechanisms and signaling pathways could further benefit the advancement of diagnostic and therapeutic strategies for EVT invasion dysregulation-related pregnancy disorders, e.g., pre-eclampsia. Reference: (1) Li Yan et al., Trends Endocrinol Metab 2021 18: S1043-2760(20)30266-6. (2) Hong-Jin Zhao et al., FASEB J 2020;34(2):3151-3164. (3) Hong-Jin Zhao et al., Cell Death Dis 2018;9(2):174.

Bone Morphogenetic Protein 2 Increases Human Trophoblast Invasion by Up-Regulating Integrin Beta3

The adequate invasion of extravillous trophoblast cells (EVTs) is indispensable for the implantation of embryos and subsequent remodeling of uterine spiral arteries in early human gestation. Bone morphogenetic protein 2 (BMP2), which is abundantly expressed at the maternal-fetal interface, has been shown to promote the human EVT invasion process (1). Integrin switching (i.e., a switch from α6β4 to αvβ3) plays essential roles in cell-extracellular matrix adhesion and has been reported to influence EVT migration and invasion (2). Moreover, integrin β3 has been found to promote the adhesion, invasion, and migration abilities of embryonic trophoblasts (3). However, whether integrin β3 participates in BMP2 signaling and mediates BMP2-increased-human trophoblast invasion remains unknown. The purpose of our study was to explore the effects of BMP2 on integrin αvβ3 expression and the possible mediation role of integrin β3 in BMP2-regulated human trophoblast invasion. We used immortalized human trophoblast cell line (HTR8/SVneo) and primary human extravillous trophoblast cells (EVTs) isolated from first-trimester villi as study models. RT-qPCR and Western blot assay were respectively utilized to detect the messenger RNA and protein levels of intergrin αv and β3. The function of the target protein was studied by siRNA knockdown, and the trophoblast invasion ability was checked by Matrigel-coated transwell invasion assays. Our results demonstrated that the mRNA and protein levels of integrin β3, rather than integrin αv, were up-regulated after BMP2 treatment in HTR8/SVneo and primary EVT cells. Importantly, siRNA-mediated down-regulation of integrin β3 significantly inhibited basal and BMP2-induced HTR8/SVneo cell invasionas measured by transwell invasion assay. In conclusion, we findings support that BMP2 promotes human trophoblast cell invasion by up-regulating integrin β3 expression, benefiting the in-depth understanding of the pro-invasive effect of BMP2 on human trophoblasts during early pregnancy. Reference: (1) Hong-Jin Zhao et al., Cell Death Dis 2018;9:174. (2) Damsky, C.H. et al, Development 1994; 120, 3657-3666. (3) Dong-Mei He et al., Reproduction 2019;157:423-430.