BMP Stimulation Differentially Affects Phosphorylation and Protein Stability of ß-Catenin in Breast Cancer Cell Lines.

Increased expression and nuclear translocation of ß-CATENIN is frequently observed in breast cancer, and it correlates with poor prognosis. Current treatment strategies targeting ß-CATENIN are not as efficient as desired. Therefore, detailed understanding of ß-CATENIN regulation is crucial. Bone morphogenetic proteins (BMP) and Wingless/Integrated (WNT) pathway crosstalk is well-studied for many cancer types including colorectal cancer, whereas it is still poorly understood for breast cancer. Analysis of breast cancer patient data revealed that BMP2 and BMP6 were significantly downregulated in tumors. Since mutation frequency in genes enhancing ß-CATENIN protein stability is relatively low in breast cancer, we aimed to investigate whether decreased BMP ligand expression could contribute to a high protein level of ß-CATENIN in breast cancer cells. We demonstrated that downstream of BMP stimulation, SMAD4 is required to reduce ß-CATENIN protein stability through the phosphorylation in MCF7 and T47D cells. Consequently, BMP stimulation reduces ß-CATENIN levels and prevents its nuclear translocation and target gene expression in MCF7 cells. Conversely, BMP stimulation has no effect on ß-CATENIN phosphorylation or stability in MDA-MB-231 and MDA-MB-468 cells. Likewise, SMAD4 modulation does not alter the response of those cells, indicating that SMAD4 alone is insufficient for BMP-induced ß-CATENIN phosphorylation. While our data suggest that considering BMP activity may serve as a prognostic marker for understanding ß-CATENIN accumulation risk, further investigation is needed to elucidate the differential responsiveness of breast cancer cell lines.

Divergent and Compensatory Effects of BMP2 and BMP4 on the VSMC Phenotype and BMP4's Role in Thoracic Aortic Aneurysm Development.

Vascular smooth muscle cells (VSMCs) play a key role in aortic aneurysm formation. Bone morphogenetic proteins (BMPs) have been implicated as important regulators of VSMC phenotype, and dysregulation of the BMP pathway has been shown to be associated with vascular diseases. The aim of this study was to investigate for the first time the effects of BMP-4 on the VSMC phenotype and to understand its role in the development of thoracic aortic aneurysms (TAAs). Using the angiotensin II (AngII) osmotic pump model in mice, aortas from mice with VSMC-specific BMP-4 deficiency showed changes similar to AngII-infused aortas, characterised by a loss of contractile markers, increased fibrosis, and activation of matrix metalloproteinase 9. When BMP-4 deficiency was combined with AngII infusion, there was a significantly higher rate of apoptosis and aortic dilatation. In vitro, VSMCs with mRNA silencing of BMP-4 displayed a dedifferentiated phenotype with activated canonical BMP signalling. In contrast, BMP-2-deficient VSMCs exhibited the opposite phenotype. The compensatory regulation between BMP-2 and BMP-4, with BMP-4 promoting the contractile phenotype, appeared to be independent of the canonical signalling pathway. Taken together, these results demonstrate the impact of VSMC-specific BMP-4 deficiency on TAA development.

Mesenchymal Stem Cell Exosomes Enhance Posterolateral Spinal Fusion in a Rat Model.

Spinal fusion, a common surgery performed for degenerative lumbar conditions, often uses recombinant human bone morphogenetic protein 2 (rhBMP-2) that is associated with adverse effects. Mesenchymal stromal/stem cells (MSCs) and their extracellular vesicles (EVs), particularly exosomes, have demonstrated efficacy in bone and cartilage repair. However, the efficacy of MSC exosomes in spinal fusion remains to be ascertained. This study investigates the fusion efficacy of MSC exosomes delivered via an absorbable collagen sponge packed in a poly Ɛ-caprolactone tricalcium phosphate (PCL-TCP) scaffold in a rat posterolateral spinal fusion model. Herein, it is shown that a single implantation of exosome-supplemented collagen sponge packed in PCL-TCP scaffold enhanced spinal fusion and improved mechanical stability by inducing bone formation and bridging between the transverse processes, as evidenced by significant improvements in fusion score and rate, bone structural parameters, histology, stiffness, and range of motion. This study demonstrates for the first time that MSC exosomes promote bone formation to enhance spinal fusion and mechanical stability in a rat model, supporting its translational potential for application in spinal fusion.

Polydopamine-mediated immobilization of BMP-2 onto electrospun nanofibers enhances bone regeneration.

Dealing with bone defects is a significant challenge to global health. Electrospinning in bone tissue engineering has emerged as a solution to this problem. In this study, we designed a PVDF-b-PTFE block copolymer by incorporating TFE, which induced a phase shift in PVDF fromαtoß, thereby enhancing the piezoelectric effect. Utilizing the electrospinning process, we not only converted the material into a film with a significant surface area and high porosity but also intensified the piezoelectric effect. Then we used polydopamine to immobilize BMP-2 onto PVDF-b-PTFE electrospun nanofibrous membranes, achieving a controlled release of BMP-2. The scaffold's characters were examined using SEM and XRD. To assess its osteogenic effectsin vitro, we monitored the proliferation of MC3T3-E1 cells on the fibers, conducted ARS staining, and measured the expression of osteogenic genes.In vivo, bone regeneration effects were analyzed through micro-CT scanning and HE staining. ELISA assays confirmed that the sustained release of BMP-2 can be maintained for at least 28 d. SEM images and CCK-8 results demonstrated enhanced cell viability and improved adhesion in the experimental group. Furthermore, the experimental group exhibited more calcium nodules and higher expression levels of osteogenic genes, including COL-I, OCN, and RUNX2. HE staining and micro-CT scans revealed enhanced bone tissue regeneration in the defective area of the PDB group. Through extensive experimentation, we evaluated the scaffold's effectiveness in augmenting osteoblast proliferation and differentiation. This study emphasized the potential of piezoelectric PVDF-b-PTFE nanofibrous membranes with controlled BMP-2 release as a promising approach for bone tissue engineering, providing a viable solution for addressing bone defects.

Biomimetic peroxidase MOF-Fe promotes bone defect repair by inhibiting TfR2 and activating the BMP2 pathway.

BACKGROUND: Large bone defects pose a clinical treatment challenge; inhibiting transferrin receptor 2 (TfR2), which is involved in iron metabolism, can promote osteogenesis. Iron-based metal-organic frameworks (MOF-Fe) particles not only inhibit TfR2 but also serve as biomimetic catalysts to remove hydrogen peroxide in reactive oxygen species (ROS); excess ROS can disrupt the normal functions of osteoblasts, thereby hindering bone regeneration. This study explored the potential effects of MOF-Fe in increasing osteogenic activity and clearing ROS. METHODS: In vitro experiments were performed to investigate the osteogenic effects of MOF-Fe particles and assess their impact on cellular ROS levels. To further validate the role of MOF-Fe in promoting bone defect repair, we injected MOF-Fe suspensions into the femoral defects of SD rats and implanted MOF-Fe-containing hydrogel scaffolds in rabbit cranial defect models and observed their effects on bone healing. RESULTS: In vitro, the presence of MOF-Fe significantly increased the expression levels of osteogenesis-related genes and proteins compared to those in the control group. Additionally, compared to those in the untreated control group, the cells treated with MOF-Fe exhibited a significantly increased ability to remove hydrogen peroxide from ROS and generate oxygen and water within the physiological pH range. In vivo experiments further confirmed the positive effect of MOF-Fe in promoting bone defect repair. CONCLUSION: This study supports the application of MOF-Fe as an agent for bone regeneration, particularly for mitigating ROS and activating the bone morphogenetic protein (BMP) pathway, demonstrating its potential value.

rhBMP-2 induces terminal differentiation of human bone marrow mesenchymal stromal cells only by synergizing with other signals.

BACKGROUND: Recombinant human bone morphogenetic protein 2 (rhBMP-2) and human bone marrow mesenchymal stromal cells (hBM-MSCs) have been thoroughly studied for research and translational bone regeneration purposes. rhBMP-2 induces bone formation in vivo, and hBM-MSCs are its target, bone-forming cells. In this article, we studied how rhBMP-2 drives the multilineage differentiation of hBM-MSCs both in vivo and in vitro. METHODS: rhBMP-2 and hBM-MSCs were tested in an in vivo subcutaneous implantation model to assess their ability to form mature bone and undergo multilineage differentiation. Then, the hBM-MSCs were treated in vitro with rhBMP-2 for short-term or long-term cell-culture periods, alone or in combination with osteogenic, adipogenic or chondrogenic media, aiming to determine the role of rhBMP-2 in these differentiation processes. RESULTS: The data indicate that hBM-MSCs respond to rhBMP-2 in the short term but fail to differentiate in long-term culture conditions; these cells overexpress the rhBMP-2 target genes DKK1, HEY-1 and SOST osteogenesis inhibitors. However, in combination with other differentiation signals, rhBMP-2 acts as a potentiator of multilineage differentiation, not only of osteogenesis but also of adipogenesis and chondrogenesis, both in vitro and in vivo. CONCLUSIONS: Altogether, our data indicate that rhBMP-2 alone is unable to induce in vitro osteogenic terminal differentiation of hBM-MSCs, but synergizes with other signals to potentiate multiple differentiation phenotypes. Therefore, rhBMP-2 triggers on hBM-MSCs different specific phenotype differentiation depending on the signalling environment.

Tumor cell-intrinsic epigenetic SETpoint of cancer-associated fibroblasts.

Cancer-associated fibroblasts (CAFs) exhibit spatial and functional diversity. Here, Niu et al. unveil SETD2's function in lipid metabolism and CAF heterogeneity in pancreatic ductal adenocarcinoma. SETD2 deficiency boosts oxidative phosphorylation activity, prompting lipid-laden CAF formation through BMP2 signaling, offering promising therapeutic avenues in personalized cancer treatment.

The role of the Piezo1 channel in osteoblasts under cyclic stretching: A study on osteogenic and osteoclast factors.

OBJECTIVES: Orthodontic tooth movement is a mechanobiological reaction induced by appropriate forces, including bone remodeling. The mechanosensitive Piezo channels have been shown to contribute to bone remodeling. However, information about the pathways through which Piezo channels affects osteoblasts remains limited. Thus, we aimed to investigate the influence of Piezo1 on the osteogenic and osteoclast factors in osteoblasts under mechanical load. MATERIALS AND METHODS: Cyclic stretch (CS) experiments on MC3T3-E1 were conducted using a BioDynamic mechanical stretching device. The Piezo1 channel blocker GsMTx4 and the Piezo1 channel agonist Yoda1 were used 12 h before the application of CS. MC3T3-E1 cells were then subjected to 15% CS, and the expression of Piezo1, Piezo2, BMP-2, OCN, Runx2, RANKL, p-p65/p65, and ALP was measured using quantitative real-time polymerase chain reaction, western blot, alkaline phosphatase staining, and immunofluorescence staining. RESULTS: CS of 15% induced the highest expression of Piezo channel and osteoblast factors. Yoda1 significantly increased the CS-upregulated expression of Piezo1 and ALP activity but not Piezo2 and RANKL. GsMTx4 downregulated the CS-upregulated expression of Piezo1, Piezo2, Runx2, OCN, p-65/65, and ALP activity but could not completely reduce CS-upregulated BMP-2. CONCLUSIONS: The appropriate force is more suitable for promoting osteogenic differentiation in MC3T3-E1. The Piezo1 channel participates in osteogenic differentiation of osteoblasts through its influence on the expression of osteogenic factors like BMP-2, Runx2, and OCN and is involved in regulating osteoclasts by influencing phosphorylated p65. These results provide a foundation for further exploration of osteoblast function in orthodontic tooth movement.

Control of neuronal excitation-inhibition balance by BMP-SMAD1 signalling.

Throughout life, neuronal networks in the mammalian neocortex maintain a balance of excitation and inhibition, which is essential for neuronal computation1,2. Deviations from a balanced state have been linked to neurodevelopmental disorders, and severe disruptions result in epilepsy3-5. To maintain balance, neuronal microcircuits composed of excitatory and inhibitory neurons sense alterations in neural activity and adjust neuronal connectivity and function. Here we identify a signalling pathway in the adult mouse neocortex that is activated in response to increased neuronal network activity. Overactivation of excitatory neurons is signalled to the network through an increase in the levels of BMP2, a growth factor that is well known for its role as a morphogen in embryonic development. BMP2 acts on parvalbumin-expressing (PV) interneurons through the transcription factor SMAD1, which controls an array of glutamatergic synapse proteins and components of perineuronal nets. PV-interneuron-specific disruption of BMP2-SMAD1 signalling is accompanied by a loss of glutamatergic innervation in PV cells, underdeveloped perineuronal nets and decreased excitability. Ultimately, this impairment of the functional recruitment of PV interneurons disrupts the cortical excitation-inhibition balance, with mice exhibiting spontaneous epileptic seizures. Our findings suggest that developmental morphogen signalling is repurposed to stabilize cortical networks in the adult mammalian brain.

Osteogenic Effects of the Diospyros lotus L. Leaf Extract on MC3T3-E1 Pre-Osteoblasts and Ovariectomized Mice via BMP2/4 and TGF ß Pathways.

Osteoporosis, a disease defined by the primary bone strength due to a low bone mineral density, is a bone disorder associated with increased mortality in the older adult population. Osteoporosis is mainly treated via hormone replacement therapy, bisphosphates, and anti-bone resorption agents. However, these agents exert severe side effects, necessitating the development of novel therapeutic agents. Many studies are focusing on osteogenic agents as they increase the bone density, which is essential for osteoporosis treatment. Here, we aimed to investigate the effects of Diospyros lotus L. leaf extract (DLE) and its components on osteoporosis in MC3T3-E1 pre-osteoblasts and ovariectomized mice and to elucidate the underlying related pathways. DLE enhanced the differentiation of MC3T3-E1 pre-osteoblasts, with a 1.5-fold elevation in ALP activity, and increased the levels of osteogenic molecules, RUNX family transcription factor 2, and osterix. This alteration resulted from the activation of bone morphogenic protein 2/4 (BMP2/4) and transformation of growth factor ß (TGF ß) pathways. In ovariectomized mice, DLE suppressed the decrease in bone mineral density by 50% and improved the expression of other bone markers, which was confirmed by the 3~40-fold increase in osteogenic proteins and mRNA expression levels in bone marrow cells. The three major compounds identified in DLE exhibited osteogenic and estrogenic activities with their aglycones, as previously reported. Among the major compounds, myricitrin alone was not as strong as whole DLE with all its constituents. The osteogenic activity of DLE was partially suppressed by the inhibitor of estrogen signaling, indicating that the estrogenic activity of DLE participated in its osteogenic activity. Overall, DLE suppresses osteoporosis by inducing osteoblast differentiation.

BMP2-ERK-ATF4 Axis-Based 6-methoxybenzofuran Compound I-9 Acts as Candidate Drug for Bone Formation and Anti-Osteoporosis.

As the global population ages, the number of patients with osteoporosis is rapidly rising. The existing first-line clinical drugs are bone resorption inhibitors that have difficulty restoring the bone mass of elderly patients to the safe range. The range and period of use of existing peptides and monoclonal antibodies are limited, and small-molecule bone formation-promoting drugs are urgently required. We established an I-9 synthesis route with high yield, simple operation, and low cost that was suitable for future large-scale production. I-9 administration promoted bone formation and increased bone mass in mice with low bone mass in an aged C57 mouse model. Our findings revealed a hitherto undescribed pathway involving the BMP2-ERK-ATF4 axis that promotes osteoblast differentiation; I-9 has favorable biosafety in mice. This study systematically investigated the efficacy, safety, and mechanism of I-9 for treating osteoporosis and positions this drug for preclinical research in the future. Thus, this study has promoted the development of small-molecule bone-promoting drugs.

Noggin promotes osteogenesis in human adipose-derived mesenchymal stem cells via FGFR2/Src/Akt and ERK signaling pathway.

The balance between Noggin and bone morphogenetic proteins (BMPs) is important during early development and skeletal regenerative therapies. Noggin binds BMPs in the extracellular space, thereby preventing BMP signaling. However, Noggin may affect cell response not necessarily through the modulation of BMP signaling, raising the possibility of direct Noggin signaling through yet unspecified receptors. Here we show that in osteogenic cultures of adipose-derived stem cells (ASCs), Noggin activates fibroblast growth factor receptors (FGFRs), Src/Akt and ERK kinases, and it stabilizes TAZ proteins in the presence of dexamethasone. Overall, this leads ASCs to increased expression of osteogenic markers and robust mineral deposition. Our results also indicate that Noggin can induce osteogenic genes expression in normal human bone marrow stem cells and alkaline phosphatase activity in normal human dental pulp stem cells. Besides, Noggin can specifically activate FGFR2 in osteosarcoma cells. We believe our findings open new research avenues to further explore the involvement of Noggin in cell fate modulation by FGFR2/Src/Akt/ERK signaling and potential applications of Noggin in bone regenerative therapies.

Litsea glutinosa extract promotes fracture healing and prevents bone loss via BMP2/SMAD1 signaling.

Estrogen deficiency is one of the main causes for postmenopausal osteoporosis. Current osteoporotic therapies are of high cost and associated with serious side effects. So there is an urgent need for cost-effective anti-osteoporotic agents. Anti-osteoporotic activity of Litsea glutinosa extract (LGE) is less explored. Moreover, its role in fracture healing and mechanism of action is still unknown. In the present study we explore the osteoprotective potential of LGE in osteoblast cells and fractured and ovariectomized (Ovx) mice models. Alkaline phosphatase (ALP), MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and mineralization assays revealed that LGE treatment increased osteoblast cell differentiation, viability and mineralization. LGE treatment at 0.01 µg increased the expression of BMP2, PSMAD, RUNX2 and type 1 col. LGE also mitigated RANKL-induced osteoclastogenesis. Next, drill hole injury Balb/C mice model was treated with LGE for 12 days. Micro-CT analysis and Calcein labeling at the fracture site showed that LGE (20 mg/kg) enhanced new bone formation and bone regeneration, also increased expression of BMP2/SMAD1 signaling genes at fracture site. Ovx mice were treated with LGE for 1 month. µCT analysis indicated that the treatment of LGE at 20 mg/kg dose prevented the alteration in bone microarchitecture and maintained bone mineral density and bone mineral content. Treatment also increased bone strength and restored the bone turnover markers. Furthermore, in bone samples, LGE increased osteogenesis by enhancing the expression of BMP2/SMAD1 signaling components and decreased osteoclast number and surface. We conclude that LGE promotes osteogenesis via modulating the BMP2/SMAD1 signaling pathway. The study advocates the therapeutic potential of LGE in osteoporosis treatment.

Effects of aflatoxin and fumonisin on gene expression of growth factors and inflammation-related genes in a human hepatocyte cell line.

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely distributed in maize and maized-based products, often occurring together. The implications of co-exposure to aflatoxin and fumonsin for human health are numerous, but a particular concern is the potential of FB1 to modulate AFB1 hepatotoxicity. This study evaluated the toxicity of these mycotoxins, alone or combined, in a human non-tumorigenic liver cell line, HHL-16 cells, and assessed the effects of AFB1 and FB1 on expression of genes involved in immune and growth factor pathways. The results demonstrated that in HHL-16 cells, both AFB1 and FB1 had dose-dependent and time-dependent toxicity, and the combination of them showed a synergistic toxicity in the cells. Moreover, AFB1 caused upregulation of IL6, CCL20, and BMP2, and downregulation of NDP. In combination of AFB1 with FB1, gene expression levels of IL6 and BMP2 were significantly higher compared to individual FB1 treatment, and had a tendency to be higher than individual AFB1 treatment. This study shows that FB1 may increase the hepatoxicity of AFB1 through increasing the inflammatory response and disrupting cell growth pathways.

Excess glucocorticoids inhibit murine bone turnover via modulating the immunometabolism of the skeletal microenvironment.

Elevated bone resorption and diminished bone formation have been recognized as the primary features of glucocorticoid-associated skeletal disorders. However, the direct effects of excess glucocorticoids on bone turnover remain unclear. Here, we explored the outcomes of exogenous glucocorticoid treatment on bone loss and delayed fracture healing in mice and found that reduced bone turnover was a dominant feature, resulting in a net loss of bone mass. The primary effect of glucocorticoids on osteogenic differentiation was not inhibitory; instead, they cooperated with macrophages to facilitate osteogenesis. Impaired local nutrient status - notably, obstructed fatty acid transportation - was a key factor contributing to glucocorticoid-induced impairment of bone turnover in vivo. Furthermore, fatty acid oxidation in macrophages fueled the ability of glucocorticoid-liganded receptors to enter the nucleus and then promoted the expression of BMP2, a key cytokine that facilitates osteogenesis. Metabolic reprogramming by localized fatty acid delivery partly rescued glucocorticoid-induced pathology by restoring a healthier immune-metabolic milieu. These data provide insights into the multifactorial metabolic mechanisms by which glucocorticoids generate skeletal disorders, thus suggesting possible therapeutic avenues.

Enhanced bone regeneration in rat calvarial defects through BMP2 release from engineered poly(ethylene glycol) hydrogels.

The clinical standard therapy for large bone defects, typically addressed through autograft or allograft donor tissue, faces significant limitations. Tissue engineering offers a promising alternative strategy for the regeneration of substantial bone lesions. In this study, we harnessed poly(ethylene glycol) (PEG)-based hydrogels, optimizing critical parameters including stiffness, incorporation of arginine-glycine-aspartic acid (RGD) cell adhesion motifs, degradability, and the release of BMP2 to promote bone formation. In vitro we demonstrated that human bone marrow derived stromal cell (hBMSC) proliferation and spreading strongly correlates with hydrogel stiffness and adhesion to RGD peptide motifs. Moreover, the incorporation of the osteogenic growth factor BMP2 into the hydrogels enabled sustained release, effectively inducing bone regeneration in encapsulated progenitor cells. When used in vivo to treat calvarial defects in rats, we showed that hydrogels of low and intermediate stiffness optimally facilitated cell migration, proliferation, and differentiation promoting the efficient repair of bone defects. Our comprehensive in vitro and in vivo findings collectively suggest that the developed hydrogels hold significant promise for clinical translation for bone repair and regeneration by delivering sustained and controlled stimuli from active signaling molecules.

Sulfation of hyaluronic acid reconfigures the mechanistic pathway of bone morphogenetic protein-2 aggregation.

Bone morphogenetic protein-2 (BMP-2) is a critical growth factor of bone extracellular matrix (ECM), pivotal for osteogenesis. Glycosaminoglycans (GAGs), another vital ECM biomolecules, interact with growth factors, affecting signal transduction. Our study primarily focused on hyaluronic acid (HA), a prevalent GAG, and its sulfated derivative (SHA). We explored their impact on BMP-2's conformation, aggregation, and mechanistic pathways of aggregation using diverse optical and rheological methods. In the presence of HA and SHA, the secondary structure of BMP-2 underwent a structured transformation, characterized by a substantial increase in beta sheet content, and a detrimental alteration, manifesting as a shift towards unstructured content, respectively. Although both HA and SHA induced BMP-2 aggregation, their mechanisms differed. SHA led to rapid amorphous aggregates, while HA promoted amyloid fibrils with a lag phase and sigmoidal kinetics. Aggregate size and shape varied; HA produced larger structures, SHA smaller. Each aggregation type followed distinct pathways influenced by viscosity and excluded volume. Higher viscosity, low diffusivity of protein and higher excluded volume In the presence of HA promotes fibrillation having size in micrometer range. Low viscosity, high diffusivity of protein and lesser excluded volume leads to amorphous aggregate of size in nanometer range.

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

BACKGROUND: 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. METHODS: 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. RESULTS: We found that BMP2 was aberrantly low in midluteal phase endometrial tissues from patients with RIF. Recombinant human BMP2 treatment upregulated integrin ß3 (ITGB3) in a SMAD2/3-SMAD4 signaling-dependent manner in both HTR8/SVneo cells and primary trophoblast cells. siRNA-mediated integrin ß3 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. CONCLUSION: 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.

Stiffness and BMP-2 Mimetic Peptide Jointly Regulate the Osteogenic Differentiation of Rat Bone Marrow Stromal Cells in a Gelatin Cryogel.

Both biochemical and mechanical cues could regulate the function of stem cells, but the interaction mechanism of their signaling pathway remains unclear, especially in the three-dimensional (3D) culture mode. Higher matrix stiffness promotes osteogenic differentiation of stem cells, and bone morphogenic protein-2 (BMP-2) has been clinically applied to promote bone regeneration. Here, the crosstalk of extracellular mechanical signals on BMP-2 signaling was investigated in rat bone marrow stromal cells (rMSCs) cultured inside cryogels with interconnective pores. Stiff cryogel independently promoted osteogenic differentiation and enhanced the autocrine secretion of BMP-2, thus stimulating increased phosphorylation levels of the Smad1/5/8 complex. BMP-2 mimetic peptide (BMMP) and high cryogel stiffness jointly guided the osteogenic differentiation of rMSCs. Inhibition of rho-associated kinase (ROCK) by Y-27632 or inhibition of nonmuscle myosin II (NM II) by blebbistatin showed that osteogenesis induction by BMP-2 signaling, as well as autocrine secretion of BMP-2 and phosphorylation of the Smad complex, requires the involvement of cytoskeletal tension and ROCK pathway signaling. An interconnective microporous cryogel scaffold promoted rMSC osteogenic differentiation by combining matrix stiffness and BMMP, and it accelerated critical cranial defect repair in the rat model.

BMP2 restores erectile dysfunction through neurovascular regeneration and fibrosis reduction in diabetic mice.

BACKGROUND: The odds of erectile dysfunction are three times more prevalent in diabetes. Severe peripheral vascular and neural damage in diabetic patients responds poorly to phosphodiesterase-5 (PDE5) inhibitors. However, bone morphogenetic protein 2 is known to be involved in angiogenesis. OBJECTIVES: To assess the efficacy of bone morphogenetic protein 2 in stimulating angiogenesis and augmenting nerve regeneration in a mouse model of diabetic-induced erectile dysfunction. MATERIALS AND METHODS: The induction of diabetes mellitus was performed by streptozotocin (50 mg/kg daily) administered intraperitoneally for 5 successive days to male C57BL/6 mice that were 8 weeks old. Eight weeks post-inductions, animals were allocated to one of five groups: a control group, a streptozotocin-induced diabetic mouse group receiving two intracavernous 20 µL phosphate-buffered saline injections, or one of three bone morphogenetic protein 2 groups administered two injections of bone morphogenetic protein 2 protein (1, 5, or 10 µg) diluted in 20 µL of phosphate-buffered saline within a 3-day interval between the first and second injections. The erectile functions were assessed 2 weeks after phosphate-buffered saline or bone morphogenetic protein 2 protein injections by recording the intracavernous pressure through cavernous nerve electrical stimulation. Angiogenic activities and nerve regenerating effects of bone morphogenetic protein 2 were determined in penile tissues, aorta, vena cava, the main pelvic ganglions, the dorsal roots, and from the primary cultured mouse cavernous endothelial cells. Moreover, fibrosis-related factor protein expressions were evaluated by western blotting. RESULTS: Erectile function recovery to 81% of the control value in diabetic mice was found with intracavernous bone morphogenetic protein 2 injection (5 µg/20 µL). Pericytes and endothelial cells were extensively restored. It was confirmed that angiogenesis was promoted in the corpus cavernosum of diabetic mice treated with bone morphogenetic protein 2 through increased ex vivo sprouting of aortic rings, vena cava and penile tissues, and migration and tube formation of mouse cavernous endothelial cells. Bone morphogenetic protein 2 protein enhanced cell proliferation and reduced apoptosis in mouse cavernous endothelial cells and penile tissues, and promoted neurite outgrowth in major pelvic ganglia and dorsal root ganglia under high-glucose conditions. Furthermore, bone morphogenetic protein 2 suppressed fibrosis by reducing mouse cavernous endothelial cell fibronectin, collagen 1, and collagen 4 levels under high-glucose conditions. CONCLUSION: Bone morphogenetic protein 2 modulates neurovascular regeneration and inhibits fibrosis to revive the mouse erection function in diabetic conditions. Our findings propose that the bone morphogenetic protein 2 protein represents a novel and promising approach to treating diabetes-related erectile dysfunction.