Bone Morphogenetic Proteins: structure, biological function and therapeutic applications

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.

Upregulated bone morphogenetic protein 8A (BMP8A) in triple negative breast cancer (TNBC) and its involvement in the bone metastasis

Objective

The present study aimed to investigate the involvement of aberrant BMP8A expression in TNBC and bone metastasis.

Methods

Aberrant expression of BMP8A in breast cancer was first determined by analyzing The Cancer Genome Atlas breast cancer cohort (TCGA-BRCA) and an immunohistochemical (IHC) staining of BMP8A in a breast cancer tissue microarray (TMA). Clinical relevance of deregulated BMP8A in breast cancer was assessed using Kaplan-Meier online analysis. The influence of BMP8A on cellular functions of two TNBC cell lines was assessed using in vitro assays. Conditional medium (CM) collected from the supernatant of hFOB cells and bone matrix extract (BME) was applied to mimic the bone micro-environment to evaluate the role played by BMP8A in bone metastasis. Correlations with both osteolytic and osteoblastic markers were evaluated in the TCGA-BRCA cohort. Expression of certain responsive genes was quantified in the BMP8A overexpression cell lines. Additionally, signal transduction through both Smad-dependent and independent pathways was evaluated using Western blot assay.

Results

Compared to the adjacent normal tissues, BMP8A expression was significantly increased in primary tumors (p < 0.05) which was associated with shorter distant metastasis free survival (DMFS) in TNBC (p < 0.05). BMP8A was observed to enhance cell invasion and migration within TNBC cells. In the simulated bone milieu, both MDA-MB-231BMP8Aexp and BT549BMP8Aexp cells presented enhanced invasiveness. BMP8A level was strongly correlated with most osteolytic and osteoblastic markers, suggesting the potential involvement of BMP8A in bone metastasis in TNBC. Receptor activator of nuclear factor kappa-B ligand (RANKL) expression was significantly increased in BMP8A overexpressed triple-negative cell lines (MDA-MB-231 and BT549). Furthermore, enhanced phosphorylation of Smad3 and increased expression of epidermal growth factor receptor (EGFR) were observed in MDA-MB-231 cells overexpressing BMP8A.

Conclusion

BMP8A was upregulated in TNBC which was associated with poorer DMFS. BMP8A overexpression enhanced the invasion and migration of TNBC cells. With a putative role in osteolytic bone metastasis in TNBC, BMP8A represents a promising candidate for further investigation into its therapeutic potential.

The Incorporation of Zinc into Hydroxyapatite and Its Influence on the Cellular Response to Biomaterials: A Systematic Review

Zinc is known for its role in enhancing bone metabolism, cell proliferation, and tissue regeneration. Several studies proposed the incorporation of zinc into hydroxyapatite (HA) to produce biomaterials (ZnHA) that stimulate and accelerate bone healing. This systematic review aimed to understand the physicochemical characteristics of zinc-doped HA-based biomaterials and the evidence of their biological effects on osteoblastic cells. A comprehensive literature search was conducted from 2022 to 2024, covering all years of publications, in three databases (Web of Science, PUBMED, Scopus), retrieving 609 entries, with 36 articles included in the analysis according to the selection criteria. The selected studies provided data on the material's physicochemical properties, the methods of zinc incorporation, and the biological effects of ZnHA on bone cells. The production of ZnHA typically involves the wet chemical synthesis of HA and ZnHA precursors, followed by deposition on substrates using processes such as liquid precursor plasma spraying (LPPS). Characterization techniques confirmed the successful incorporation of zinc into the HA lattice. The findings indicated that zinc incorporation into HA at low concentrations is non-cytotoxic and beneficial for bone cells. ZnHA was found to stimulate cell proliferation, adhesion, and the production of osteogenic factors, thereby promoting in vitro mineralization. However, the optimal zinc concentration for the desired effects varied across studies, making it challenging to establish a standardized concentration. ZnHA materials are biocompatible and enhance osteoblast proliferation and differentiation. However, the mechanisms of zinc release and the ideal concentrations for optimal tissue regeneration require further investigation. Standardizing these parameters is essential for the effective clinical application of ZnHA.

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

Targeted expression of a designed fusion protein containing BMP2 into the lumen of exosomes

BACKGROUND

Exosomes are 30-150 nm membrane vesicles, originating from the endocytic pathway. By acting as natural carriers of biomolecules, they can transfer various materials to recipient cells. Therefore, discovering novel strategies for cargo packaging into exosomes is crucial.

METHODS

The fusion constructs, consisting of protein of interest (BMP2) along with the targeting motif, linkers, tracking proteins, and enzyme cleavage sites, were computationally designed. Following the homology modeling, the best structure was selected and subjected to molecular dynamics (MD) simulation and docking analyses. The fusion protein gene was expressed in the HEK-293LTV cell line. The high-efficiency transfected and transduced cells were screened and their exosomes were isolated. Finally, cell and exosome lysates were evaluated for expression of the fusion protein.

RESULTS

A total of 12 constructs with lengths ranging from 483 to 496 were designed. The top three templates, 1REW, 2H5Q, and 2MOF were screened. MD simulation and docking analyses of the structures revealed their stability and functionality. In the protein expression analyses, three bands at sizes of approximately 60, 25, and 12.5 kDa were observed, consistent with the sizes of the complete fusion protein, dimeric, and monomeric BMP2 protein. The presence of a 12.5 kDa band at exosome lysate analysis might suggest that it was loaded and cleaved inside exosomes.

CONCLUSION

In summary, these findings revealed that the proposed idea for cargo sorting within the exosome lumen through incorporating an appropriate cleavage site was effective, thus providing further insight into the potential of exosomes as nano-shuttles bearing therapeutic biomolecules.

BMP8B Activates Both SMAD2/3 and NF-κB Signals to Inhibit the Differentiation of 3T3-L1 Preadipocytes into Mature Adipocytes

Bone morphogenetic protein 8B (BMP8B) has been found to regulate the thermogenesis of brown adipose tissue (BAT) and the browning process of white adipose tissue (WAT). However, there is no available information regarding the role of BMP8B in the process of adipocyte differentiation. Here, we showed that BMP8B down-regulates transcriptional regulators PPARγ and C/EBPα, thereby impeding the differentiation of 3T3-L1 preadipocytes into fully mature adipocytes. BMP8B increased the phosphorylation levels of SMAD2/3, and TP0427736 HCl (SMAD2/3 inhibitor) significantly reduced the ability of BMP8B to inhibit adipocyte differentiation, suggesting that BMP8B repressed adipocyte differentiation through the SMAD2/3 pathway. Moreover, the knockdown of BMP I receptor ALK4 significantly reduced the inhibitory effect of BMP8B on adipogenesis, indicating that BMP8B triggers SMAD2/3 signaling to suppress adipogenesis via ALK4. In addition, BMP8B activated the NF-κB signal, which has been demonstrated to impede PPARγ expression. Collectively, our data demonstrated that BMP8B activates both SMAD2/3 and NF-κB signals to inhibit adipocyte differentiation. We provide previously unidentified insight into BMP8B-mediated adipogenesis.

A bone morphogenetic protein regulates the shell formation of Crassostrea gigas under ocean acidification

Bone morphogenetic proteins (BMPs) are key factors controlling osteoblast differentiation, which have been proved to be involved in the hard tissue formation of marine mollusks. In the present study, a member of BMPs gene (CgBMP7) was identified from Pacific oyster Crassostrea gigas (C. gigas) with the aim to understand its possible role in the regulation of shell formation under ocean acidification (OA) conditions. The open reading frame (ORF) of CgBMP7 was of 1254 bp encoding a polypeptide of 417 amino acids. The deduced amino acid sequence of CgBMP7 was comprised of one signal peptide, one prodomain and one TGF-β domain, which shared 21.69%-61.10% identities with those from other species. The mRNA transcript of CgBMP7 was ubiquitously expressed in all the tested tissues of adult oysters with a higher expression level in mantle, notably highest in the middle fold (MF) of the three folds of mantle. The expression level of bone morphogenetic protein type I receptor (CgBMPR1B) mRNA was also highest in the MF and up-regulated dramatically post recombinant BMP7 protein (rCgBMP7) stimulation. After the blockage of BMPR1B with inhibitor LDN193189 (LDN), the mRNA expression level and phosphorylation level of CgSmad1/5/8 in mantle were decreased, and the mRNA expression levels of CgCaM and Cgengrailed-1 were down-regulated significantly. During the oysters were exposed to acidified seawater for weeks, the expression levels of CgBMP7, CgBMPR1B and CgSmad1/5/8 in the MF decreased significantly (p < 0.01) at the 4th week, and CgCaM and Cgengrailed-1 also exhibited the same variable expression patterns as CgBMP7. In addition, the growth of shell in the treatment group (pH 7.8) was slower than that in the control group (pH 8.1). These results collectively indicated that BMP7 was able to trigger the BMPR-Smad signaling pathway and involved in controlling the formation of oyster calcified shell under OA conditions.

Ataluren prevented bone loss induced by ovariectomy and aging in mice through the BMP-SMAD signaling pathway

Both estrogen deficiency and aging may lead to osteoporosis. Developing novel drugs for treating osteoporosis is a popular research direction. We screened several potential therapeutic agents through a new deep learning-based efficacy prediction system (DLEPS) using transcriptional profiles for osteoporosis. DLEPS screening led to a potential novel drug examinee, ataluren, for treating osteoporosis. Ataluren significantly reversed bone loss in ovariectomized mice. Next, ataluren significantly increased human bone marrow-derived mesenchymal stem cell (hBMMSC) osteogenic differentiation without cytotoxicity, indicated by the high expression index of osteogenic differentiation genes (OCN , BGLAP, ALP, COL1A, BMP2, RUNX2). Mechanistically, ataluren exerted its function through the BMP-SMAD pathway. Furthermore, it activated SMAD phosphorylation but osteogenic differentiation was attenuated by BMP2-SMAD inhibitors or small interfering RNA of BMP2. Finally, ataluren significantly reversed bone loss in aged mice. In summary, our findings suggest that the DLEPS-screened ataluren may be a therapeutic agent against osteoporosis by aiding hBMMSC osteogenic differentiation.

Bmp8a deletion leads to obesity through regulation of lipid metabolism and adipocyte differentiation

The role of bone morphogenetic proteins (BMPs) in regulating adipose has recently become a field of interest. However, the underlying mechanism of this effect has not been elucidated. Here we show that the anti-fat effect of Bmp8a is mediated by promoting fatty acid oxidation and inhibiting adipocyte differentiation. Knocking out the bmp8a gene in zebrafish results in weight gain, fatty liver, and increased fat production. The bmp8a-/- zebrafish exhibits decreased phosphorylation levels of AMPK and ACC in the liver and adipose tissues, indicating reduced fatty acid oxidation. Also, Bmp8a inhibits the differentiation of 3T3-L1 preadipocytes into mature adipocytes by activating the Smad2/3 signaling pathway, in which Smad2/3 binds to the central adipogenic factor PPARγ promoter to inhibit its transcription. In addition, lentivirus-mediated overexpression of Bmp8a in 3T3-L1 cells significantly increases NOD-like receptor, TNF, and NF-κB signaling pathways. Furthermore, NF-κB interacts with PPARγ, blocking PPARγ's activation of its target gene Fabp4, thereby inhibiting adipocyte differentiation. These data bring a signal bridge between immune regulation and adipocyte differentiation. Collectively, our findings indicate that Bmp8a plays a critical role in regulating lipid metabolism and adipogenesis, potentially providing a therapeutic approach for obesity and its comorbidities.

Recombinant sugarcane cystatin CaneCPI-5 promotes osteogenic differentiation

Cysteine proteases orchestrate bone remodeling, and are inhibited by cystatins. In reinforcing our hypothesis that exogenous and naturally obtained inhibitors of cysteine proteases (cystatins) act on bone remodeling, we decided to challenge osteoblasts with sugarcane-derived cystatin (CaneCPI-5) for up to 7 days. To this end, we investigated molecular issues related to the decisive, preliminary stages of osteoblast biology, such as adhesion, migration, proliferation, and differentiation. Our data showed that CaneCPI-5 negatively modulates both cofilin phosphorylation at Ser03, and the increase in cytoskeleton remodeling during the adhesion mechanism, possibly as a prerequisite to controlling cell proliferation and migration. This is mainly because CaneCPI-5 also caused the overexpression of the CDK2 gene, and greater migration of osteoblasts. Extracellular matrix remodeling was also evaluated in this study by investigating matrix metalloproteinase (MMP) activities. Our data showed that CaneCPI-5 overstimulates both MMP-2 and MMP-9 activities, and suggested that this cellular event could be related to osteoblast differentiation. Additionally, differentiation mechanisms were better evaluated by investigating Osterix and alkaline phosphatase (ALP) genes, and bone morphogenetic protein (BMP) signaling members. Altogether, our data showed that CaneCPI-5 can trigger biological mechanisms related to osteoblast differentiation, and broaden the perspectives for better exploring biotechnological approaches for bone disorders.

Role and Mechanism of BMP4 in Regenerative Medicine and Tissue Engineering

Bone morphogenetic protein 4 (BMP4) is emerging as a promising cytokine for regenerative medicine and tissue engineering. BMP4 has been shown to promote the regeneration of teeth, periodontal tissue, bone, cartilage, the thymus, hair, neurons, nucleus pulposus, and adipose tissue, as well as the formation of skeletal myotubes and vessels. BMP4 can also contribute to the formation of tissues in the heart, lung, and kidney. However, there are certain deficiencies, including the insufficiency of the mechanism of BMP4 in some fields and an appropriate carrier of BMP4 for clinical use. There has also been a lack of in vivo experiments and orthotopic transplantation studies in some fields. BMP4 has great distance from the clinical application. Therefore, there are many BMP4-related studies waiting to be explored. This review mainly discusses the effects, mechanisms, and applications of BMP4 in regenerative medicine and tissue engineering over the last 10 years in various domains and possible improvements. BMP4 has shown great potential in regenerative medicine and tissue engineering. The research of BMP4 has broad development space and great value.

Alcohol-induced increase in BMP levels promotes fatty liver disease in male prediabetic stage Otsuka Long-Evans Tokushima Fatty rats

Alcohol consumption exacerbates liver abnormalities in animal models, but whether it increases the severity of liver disease in early diabetic or prediabetic rats is unclear. To investigate the molecular mechanisms underlying alcohol-induced liver steatosis or hepatitis, we used a prediabetic animal model. Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Fatty (LETO) rats were pair-fed with an ethanol-containing liquid diet for 6 weeks. Compared with controls, OLETF and LETO rats displayed more pronounced liver steatosis and higher plasma levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate transaminase (SPGT), indicating liver injury. Ethanol-fed LETO (Pd-L-E) rats showed mild liver steatosis and no inflammation compared with ethanol-fed OLETF (Pd-O-E) rats. Although precursor and active SREBP-1 levels in the liver of ethanol-fed OLETF rats significantly increased compared with control diet-fed OLETF rats (Pd-O-C), those of Pd-L-E rats did not. Bone morphogenetic protein (BMP) and TGF-β1 balance in Pd-O-E rats was significantly altered because BMP signaling was upregulated by inducing BMP2, BMP4, BMP7, BMP9, Smad1, and Smad4, whereas TGF-β1, Smad3, and Erk were downregulated. Activation of TGF-β/Smad signaling inhibited BMP2 and BMP9 expression and increased epithelial-mesenchymal transition (EMT) marker levels (Hepcidin, Snail, and Twist) in the liver of LETO rats. Livers of ethanol-fed OLETF rats showed increased levels of vimentin, FSP-1, α-SMA, MMP1, MMP13, and collagen III compared with rats of other groups, whereas EMT marker levels did not change. Thus, BMP exerted anti- and/or pro-fibrotic effects in ethanol-fed rats. Therefore, BMP and TGF-β, two key members of the TGF-β superfamily, play important but diverse roles in liver steatosis in young LETO and OLETF rats.

Cyclopamine targeting hedgehog modulates nuclear control of the osteoblast activity

It is known that cellular events underlying the processes of bone maintenance, remodeling, and repair have their basis in the embryonic production of bone. Shh signaling is widely described developing important morphogenetic control in bone by modifying the activity of osteoblast. Furthermore, identifying whether it is associated with the modulation of nuclear control is very important to be the basis for further applications. Experimentally, osteoblasts were exposed with cyclopamine (CICLOP) considering up to 1 day and 7 days, here considered an acute and chronic responses respectively. Firstly, we have validated the osteogenic model in vitro by exposing the osteoblasts to classical differentiating solution up to 7 days to allow the analysis of alkaline phosphatase and mineralization. Conversely, our data shows that differentiating osteoblasts present higher activity of inflammasome-related genes, while Shh signaling members were lower, suggesting a negative feedback between them. Thereafter, to better know about the role of Shh signaling on this manner, functional assays using CICLOP (5 μM) were performed and the data validates the previously hypothesis that Shh represses inflammasome related genes activities. Altogether, our data supports the anti-inflammatory effect of Shh signaling by suppressing Tnfα, Tgfβ and inflammasome related genes during osteoblast differentiation, and this comprehension might support the understanding the molecular and cellular mechanisms related in bone regeneration by reporting molecular-related osteoblast differentiation.

Regenerative Potential of Bone Morphogenetic Protein 7-Engineered Mesenchymal Stem Cells in Ligature-Induced Periodontitis

Periodontitis is an oral disease caused by bacterial infection that has stages according to the severity of tissue destruction. The advanced stage of periodontitis presents irreversible destruction of soft and hard tissues, which finally results in loss of teeth. When conventional treatment modalities show limited results, tissue regeneration therapy is required in patients with advanced periodontitis. In the present study, we aimed to evaluate the effect of bone marrow-derived mesenchymal stem cells (BM-MSCs) delivering bone morphogenetic protein 7 (BMP7) on tissue regeneration in a periodontitis model. BMP7 is a member of the BMP family that shows bone-forming ability; however, BMPs rapid clearing and degradation and unproven efficacy make it difficult to apply it in clinical dentistry. To overcome this, we established BMP7-expressing engineered BM-MSCs (BMP7-eBMSCs) that showed superior osteogenic differentiation potential when subcutaneously transplanted with a biphasic calcium phosphate scaffold into immunocompromised mice. Furthermore, the efficacy of BMP7-eBMSC transplantation for periodontal tissue regeneration was evaluated in a rat ligature-induced periodontitis model. Upon measuring two-dimensional and three-dimensional amounts of regenerated alveolar bone using microcomputed tomography, the amounts were found to be significantly higher in the BMP7-eBMSC transplantation group than in the eBMSC transplantation group. Most importantly, fibrous periodontal ligament (PDL) tissue regeneration was also achieved upon BMP7-eBMSC transplantation, which was evaluated by calculating the modified relative connective tissue attachment. The amount of connective tissue attachment in the BMP7-eBMSC transplantation group was significantly higher than that in the ligature-induced periodontitis group, although the increase was comparable between the BMP7-eBMSC and human PDL stem cell transplantation groups. Taken together, our results suggested that sustainable release of BMP7 induces periodontal tissue regeneration and that transplantation of BMP7-eBMSCs is a feasible treatment option for periodontal regeneration. Impact Statement Periodontitis is the second most common human dental disease affecting chronic systemic diseases. Despite the tremendous efforts trying to cure the damaged periodontal tissues using tissue engineering technologies, a definitive regenerative method has not been in consensus. Researchers are seeking more feasible and abundant source of mesenchymal stem cells (MSCs), and furthermore, how to use reliable growth factors under more efficient control are the issues to be solved. In this study, we aimed to evaluate the effect of bone morphogenetic protein 7 (BMP7) gene delivering bone marrow-derived MSCs on periodontal tissue regeneration to evaluate the efficacy of BMP7 and engineered BMSCs for periodontal tissue regeneration.

Polysaccharide-Based Composite Scaffolds for Osteochondral and Enthesis Regeneration

The rotator cuff and Achilles tendons along with the anterior cruciate ligament (ACL) are frequently injured with limited healing capacity. At the soft-hard tissue interface, enthesis is prone to get damaged and its regeneration in osteochondral defects is essential for complete healing. The current clinical techniques used in suturing procedures to reattach tendons to bones need much improvement for the generation of the native interface tissue, that is, enthesis, for patients to regain their full functions. Recently, inspired by the composite native tissue, much effort has been made to fabricate composite scaffolds for enthesis tissue regeneration. This review first focuses on the studies that used composite scaffolds for the regeneration of enthesis. Then, the use of polysaccharides for osteochondral tissue engineering is reviewed and their potential for enthesis regeneration is presented based on their supporting effects on osteogenesis and chondrogenesis. Gellan gum (GG) is selected and reviewed as a promising polysaccharide due to its unique osteogenic and chondrogenic activities that help avoid the inherent weakness of dissimilar materials in composite scaffolds. In addition, original preliminary results showed that GG supports collagen type I production and upregulation of osteogenic marker genes. Impact Statement Enthesis regeneration is essential for complete and functional healing of tendon and ligament tissues. Current suturing techniques to reattach the tendon/ligament to bones have high failure rates. This review highlights the studies on biomimetic scaffolds aimed to regenerate enthesis. In addition, the potential of using polysaccharides to regenerate enthesis is discussed based on their ability to regenerate osteochondral tissues. Gellan gum is presented as a promising biopolymer that can be modified to simultaneously support bone and cartilage regeneration by providing structural continuity for the scaffold.

Effects of Chemical Additives in Refolding Buffer on Recombinant Human BMP-2 Dimerization and the Bioactivity on SaOS-2 Osteoblasts

Bone morphogenetic protein-2 (BMP-2) is a promising osteogenic agent in tissue engineering. BMP-2 is usually expressed in Escherichia coli owing to the high yield and low cost, but the protein is expressed as inclusion bodies. Thus, the bottleneck for BMP-2 production in E. coli is the refolding process. Here, we explored the effects of the refolding buffer composition on BMP-2 refolding. The BMP-2 inclusion body was solubilized in urea and subjected to refolding by the dilution method. Various additives were investigated to improve the BMP-2 refolding yield. Nonreducing SDS-PAGE showed that BMP-2 dimers, the presumably biologically active form, were detected at approximately 25 kDa. The highest yield of the BMP-2 dimers was observed in the refolding buffer that contained ionic detergents (sarkosyl and cetylpyridinium chloride) followed by zwitterionic and nonionic detergents (NDSB-195, NP-40, and Tween 80). In addition, sugars (glucose, sorbitol, and sucrose) in combination with anionic detergents (sodium dodecyl sulfate and sarkosyl) reduced BMP-2 oligomers and increased the BMP-2 dimer yield. Subsequently, the refolded BMP-2s were tested for their bioactivity using the alkaline phosphatase assay in osteogenic cells (SaOS-2), as well as the luciferase reporter assay and the calcium assays. The refolded BMP-2 showed the activities in the calcium deposition assay and the luciferase reporter assay but not in the alkaline phosphatase activity assay or the intracellular calcium assay even though the dimers were clearly detected. Therefore, the detection of the disulfide-linked dimeric BMP-2 in nonreducing SDS-PAGE is an inadequate proxy for the bioactivity of BMP-2.

The regulatory role of BMP4 in testicular Sertoli cells of Tibetan sheep

This study aimed to determine the regulatory mechanism of bone morphogenetic protein 4 (BMP4) gene in the testes of Tibetan sheep and its role in the blood-testis barrier (BTB). First, we cloned BMP4 gene for bioinformatics analysis, and detected the mRNA and protein expression levels of BMP4 in the testes of Tibetan sheep pre-puberty (3-mo-old), during sexual maturity (1-yr-old), and in adulthood (3-yr-old) by qRT-PCR and Western blot. In addition, the subcellular localization of BMP4 was analyzed by immunohistochemical staining. Next, BMP4 overexpression and silencing vectors were constructed and transfected into primary Sertoli cells (SCs) to promote and inhibit the proliferation of BMP4, respectively. Then, CCK-8 was used to detect the proliferation effect of SCs. The expression of BMP4 and downstream genes, pathway receptors, tight junction-related proteins, and cell proliferation and apoptosis-related genes in SCs were studied using qRT-PCR and Western blot. The results revealed that the relative expression of BMP4 mRNA and protein in testicular tissues of 1Y group and 3Y group was dramatically higher than that of 3M group (P < 0.01), and BMP4 protein is mainly located in SCs and Leydig cells at different development stages. The CDS region of the Tibetan sheep BMP4 gene was 1,229 bp. CCK-8 results demonstrated that the proliferation rate of BMP4 was significantly increased in the overexpression group (pc-DNA-3.1(+)-BMP4; P < 0.05). In addition, the mRNA and protein expressions of SMAD5, BMPR1A, and BMPR1B and tight junction-related proteins Claudin11, Occludin, and ZO1 were significantly increased (P < 0.05). The mRNA expression of cell proliferation-related gene Bcl2 was significantly enhanced (P < 0.05), and the expression of GDNF was enhanced (P > 0.05). The mRNA expression of apoptosis-related genes Caspase3 and Bax decreased significantly (P < 0.05), while the mRNA expression of cell cycle-related genes CyclinA2 and CDK2 increased significantly (P < 0.05). It is worth noting that the opposite results were observed after transfection with si-BMP4. In summary, what should be clear from the results reported here is that BMP4 affects testicular development by regulating the Sertoli cells and BTB, thereby modulating the spermatogenesis of Tibetan sheep.

Application of Biocompatible Scaffolds in Stem-Cell-Based Dental Tissue Engineering

Tissue engineering as an important field in regenerative medicine is a promising therapeutic approach to replace or regenerate injured tissues. It consists of three vital steps including the selection of suitable cells, formation of 3d scaffolds, and adding growth factors. Mesenchymal stem cells (MSCs) and embryonic stem cells (ESCs) are mentioned as two main sources for this approach that have been used for the treatment of various types of disorders. However, the main focus of literature in the field of dental tissue engineering is on utilizing MSCs. On the other hand, biocompatible scaffolds play a notable role in this regenerative process which is mentioned to be harmless with acceptable osteoinductivity. Their ability in inhibiting inflammatory responses also makes them powerful tools. Indeed, stem cell functions should be supported by biomaterials acting as scaffolds incorporated with biological signals. Naturally derived polymeric scaffolds and synthetically engineered polymeric/ceramic scaffolds are two main types of scaffolds regarding their materials that are defined further in this review. Various strategies of tissue bioengineering can affect the regeneration of dentin-pulp complex, periodontium regeneration, and whole teeth bioengineering. In this regard, in vivo/ex vivo experimental models have been developed recently in order to perform preclinical studies of dental tissue engineering which make it more transferable to be used for clinic uses. This review summarizes dental tissue engineering through its different components. Also, strategies of tissue bioengineering and experimental models are introduced in order to provide a perspective of the potential roles of dental tissue engineering to be used for clinical aims.

CTR9 drives osteochondral lineage differentiation of human mesenchymal stem cells via epigenetic regulation of BMP-2 signaling

Cell fate determination of human mesenchymal stem/stromal cells (hMSCs) is precisely regulated by lineage-specific transcription factors and epigenetic enzymes. We found that CTR9, a key scaffold subunit of polymerase-associated factor complex (PAFc), selectively regulates hMSC differentiation to osteoblasts and chondrocytes, but not to adipocytes. An in vivo ectopic osteogenesis assay confirmed the essentiality of CTR9 in hMSC-derived bone formation. CTR9 counteracts the activity of Enhancer Of Zeste 2 (EZH2), the epigenetic enzyme that deposits H3K27me3, in hMSCs. Accordingly, CTR9 knockdown (KD) hMSCs gain H3K27me3 mark, and the osteogenic differentiation defects of CTR9 KD hMSCs can be partially rescued by treatment with EZH2 inhibitors. Transcriptome analyses identified bone morphology protein-2 (BMP-2) as a downstream effector of CTR9. BMP-2 secretion, membrane anchorage, and the BMP-SMAD pathway were impaired in CTR9 KD MSCs, and the effects were rescued by BMP-2 supplementation. This study uncovers an epigenetic mechanism engaging the CTR9-H3K27me3-BMP-2 axis to regulate the osteochondral lineage differentiation of hMSCs.

Carrier systems for bone morphogenetic proteins: An overview of biomaterials used for dentoalveolar and maxillofacial bone regeneration

Different types of biomaterials have been used to fabricate carriers to deliver bone morphogenetic proteins (BMPs) in both dentoalveolar and maxillofacial bone regeneration procedures. Despite that absorbable collagen sponge (ACS) is considered the gold standard for BMP delivery, there is still some concerns regarding its use mainly due to its poor mechanical properties. To overcome this, novel systems are being developed, however, due to the wide variety of biomaterial combination, the heterogeneous assessment of newly formed tissue, and the intended clinical applications, there is still no consensus regarding which is more efficient in a particular clinical scenario. The combination of two or more biomaterials in different topological configurations has allowed specific controlled-release patterns for BMPs, improving their biological and mechanical properties compared with classical single-material carriers. However, more basic research is needed. Since the BMPs can be used in multiple clinical scenarios having different biological and mechanical needs, novel carriers should be developed in a context-specific manner. Thus, the purpose of this review is to gather current knowledge about biomaterials used to fabricate delivery systems for BMPs in both dentoalveolar and maxillofacial contexts. Aspects related with the biological, physical and mechanical characteristics of each biomaterial are also presented and discussed.

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Strategies for bone formation and regeneration are a major concern in dentistry.

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Topical delivery of bone morphogenetic proteins (BMPs) allows rapid bone formation.

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BMPs requires proper carrier system to allow controlled and sustained release.

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Carrier should also fulfill mechanical requirements of bone defect sites.

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By using complex composites, it would be possible to develop new carriers for BMPs.

Cytokine conjugates to elastin-like polypeptides

Cytokines are a group of pleiotropic proteins which are crucial for various biological processes and useful as therapeutics. However, they usually suffer from the poor stability, extreme short circulation half-life, difficulty in high-yield and large-scale production and side effects, which greatly restricts their applications. Over the past decades, conjugation of cytokines with elastin-like polypeptides (ELPs), a type of promising biomaterials, have showed great potential in solving these challenges due to ELP's thermal responsiveness, excellent biocompatibility and biodegradability, non-immunogenicity, and ease of design and control at the genetic level. This review presents recent progress in the design and production of a variety of ELP conjugated cytokines for extended circulation, enhanced stability, increased soluble protein expression, simplified purification, improved drug delivery, and controlled release. Notably, the unique thermoresponsive properties of cytokine-ELP conjugates make it possible to self-assemble into micelles with drastically extended circulatory half-life for targeted delivery or to in situ form drug depots for topical administration and controlled release. The challenges and issues in the emerging field are further discussed and the future directions are pointed out at the end of this review.

A single-nucleus and spatial transcriptomic atlas of the COVID-19 liver reveals topological, functional, and regenerative organ disruption in patients

The molecular underpinnings of organ dysfunction in acute COVID-19 and its potential long-term sequelae are under intense investigation. To shed light on these in the context of liver function, we performed single-nucleus RNA-seq and spatial transcriptomic profiling of livers from 17 COVID-19 decedents. We identified hepatocytes positive for SARS-CoV-2 RNA with an expression phenotype resembling infected lung epithelial cells. Integrated analysis and comparisons with healthy controls revealed extensive changes in the cellular composition and expression states in COVID-19 liver, reflecting hepatocellular injury, ductular reaction, pathologic vascular expansion, and fibrogenesis. We also observed Kupffer cell proliferation and erythrocyte progenitors for the first time in a human liver single-cell atlas, resembling similar responses in liver injury in mice and in sepsis, respectively. Despite the absence of a clinical acute liver injury phenotype, endothelial cell composition was dramatically impacted in COVID-19, concomitantly with extensive alterations and profibrogenic activation of reactive cholangiocytes and mesenchymal cells. Our atlas provides novel insights into liver physiology and pathology in COVID-19 and forms a foundational resource for its investigation and understanding.

Brown adipose tissue as an endocrine organ: updates on the emerging role of batokines

Brown adipose tissue (BAT) remains active in adults, oxidizing fatty acids or glucose and releasing energy in the form of heat. Brown adipocytes and enhanced thermogenesis are targets for treating obesity and its comorbidities. BAT shows high synthesis activity and secretes several signaling molecules. The brown adipokines, or batokines, take action in an autocrine, paracrine, and endocrine manner. Batokines have a role in the homeostasis of the cardiovascular system, central nervous system, white adipose tissue, liver, and skeletal muscle and exert beneficial effects on BAT. The systemic function of batokines gives BAT an endocrine organ profile. Besides, the batokines Fibroblast Growth Factor-21, Vascular Endothelial Growth Factor A, Bone Morphogenetic Protein 8, Neuregulin 4, Myostatin, and Interleukin-6 emerge as targets to treat obesity and its comorbidities, deserving attention. This review outlines the role of six emerging batokines on BAT and their cross-talk with other organs, focusing on their physiological significance and diet-induced changes.

Zaprinast and avanafil increase the vascular endothelial growth factor, vitamin D3, bone morphogenic proteins 4 and 7 levels in the kidney tissue of male rats applied the glucocorticoid

Objective: This study investigated effect of zaprinast and avanafil on vascular endothelial growth factor (VEGF), bone morphogenic protein (BMP) 4 and 7, and vitamin D₃ levels against the negative effect of dexamethazone.Method: Rats were randomly divided into four groups (n = 6). Control: Empty a syringe was immersed and removed subcutaneously. Dexamethasone (DEX): 120 µg/kg DEX was injected subcutaneously once a day for 28 days. DEX + zaprinast and DEX + avanafil groups: 10 mg/kg zaprinast and avanafil were administrated to rats in addition to the same procedure in the DEX, respectively. VitaminD₃, VEGF, BMP4 and 7 levels by enzyme linked immunosorbent assay (ELISA) and angiogenesis by histopathological/immunohistochemical were evaluated.Results: BMP4 values in the DEX were lower than the other groups (p < .05). DEX + zaprinast and DEX + avanafil exhibited an increase in all the parameters compared to the control and DEX (p < .05). However, these were not significant for the DEX + zaprinast (p > .05). Also, there was a significant increase in angiogenesis in the DEX + zaprinast and DEX + avanafil.Conclusion: Zaprinast and significantly avanafil induced vitamin D₃, BMP4 and 7 levels by increasing angiogenesis in renal.

The Effect of the Topmost Layer and the Type of Bone Morphogenetic Protein-2 Immobilization on the Mesenchymal Stem Cell Response

Recombinant human bone morphogenetic protein-2 (rhBMP-2) plays a key role in the stem cell response, not only via its influence on osteogenesis, but also on cellular adhesion, migration, and proliferation. However, when applied clinically, its supra-physiological levels cause many adverse effects. Therefore, there is a need to concomitantly retain the biological activity of BMP-2 and reduce its doses. Currently, the most promising strategies involve site-specific and site-directed immobilization of rhBMP-2. This work investigated the covalent and electrostatic binding of rhBMP-2 to ultrathin-multilayers with chondroitin sulfate (CS) or diazoresin (DR) as the topmost layer. Angle-resolved X-ray photoelectron spectroscopy was used to study the exposed chemical groups. The rhBMP-2 binding efficiency and protein state were studied with time-of-flight secondary ion mass spectrometry. Quartz crystal microbalance, atomic force microscopy, and enzyme-linked immunosorbent assay were used to analyze protein–substrate interactions. The effect of the topmost layer was tested on initial cell adhesion and short-term osteogenesis marker expression. The results show the highest expression of selected osteomarkers in cells cultured on the DR-ended layer, while the cellular flattening was rather poor compared to the CS-ended system. rhBMP-2 adhesion was observed only on negatively charged layers. Cell flattening became more prominent in the presence of the protein, even though the osteogenic gene expression decreased.

Can zaprinast and avanafil induce the levels of angiogenesis, bone morphogenic protein 2, 4 and 7 in kidney of ovariectomised rats?

OBJECTIVE

This study investigated effects of zaprinast and avanafil on angiogenesis, vascular endothelial growth factor (VEGF), bone morphogenic protein (BMP) 2, 4 and 7.

METHODS

Female rats were randomly divided into four groups (n = 6). Sham; abdomen was approximately 2 cm opened and closed. Ovariectomised (OVX); abdomen was opened 2 cm and the ovaries were cut. OVX + zaprinast and OVX + avanafil groups; after the same procedure with OVX, 10 mg/kg zaprinast and avanafil were orally administered for 2 month, respectively. Angiogenesis and the levels of VEGF, BMP2, 4 and 7 were determined.

RESULTS

VEGF, BMP2, 4 and 7 levels in OVX + zaprinast and especially OVX + avanafil groups were higher than the sham and OVX (p < .05). However, only VEGF and BMP2 levels in OVX + zaprinast group were significant according to sham (p < .05). Also, angiogenesis in OVX + zaprinast and OVX + avanafil groups was dominant according to sham and OVX (p < .05).

CONCLUSIONS

Zaprinast and avanafil induced BMP2, 4 and 7 levels synergistically with increased VEGF and angiogenesis in renal tissue.

Stimulating effects of vardenafil, tadalafil, and udenafil on vascular endothelial growth factor, angiogenesis, vitamin D3, bone morphogenic proteins in ovariectomized rats

OBJECTIVE

This study investigated the effect of vardenafil, tadalafil, and udenafil from phosphodiesterase-5 inhibitors (PDE-5Is) on bone morphogenic-protein (BMP)2 and 4 levels, along with angiogenesis in ovariectomized rat's kidney.

METHOD

Rats were randomly divided into five groups (n = 10). Sham: abdomen was opened, and closed. OVX: ovaries were removed. OVX + vardenafil, OVX + tadalafil, and OVX + udenafil groups: ovaries were removed and closed, and after 6 months from postoperative, 10 mg/kg of vardenafil, tadalafil, and udenafil were administrated as daily a single-dose for 60 days, respectively. Histopathologic and immunohistochemical examinations were performed for angiogenesis, and biochemical analysis for vascular endothelial growth-factor (VEGF), VitaminD₃, BMP2 and 4 levels in rat's kidney.

RESULTS

VEGF, BMP2 and 4, VitaminD₃, and angiogenesis were high in the all inhibitor groups compared with the sham and OVX (p < .05). However, BMP4 levels were only high in the OVX + tadalafil group (p < .05).

CONCLUSION

The results indicated that vardenafil, udenafil, and especially tadalafil increased VEGF, BMP2, and VitaminD₃ levels.

Computational Insights into the Structural and Functional Impacts of nsSNPs of Bone Morphogenetic Proteins

BMPs (bone morphogenetic proteins) are multipurpose (transforming growth factor)TGF-superfamily released cytokines. These glycoproteins, acting as disulfide-linked homo- or heterodimers, are highly potent regulators of bone and cartilage production and repair, cell proliferation throughout embryonic development, and bone homeostasis in the adults. Due to the fact that genetic variation might influence structural functions, this study is aimed to determine the pathogenic effect of nonsynonymous single-nucleotide polymorphisms (nsSNPs) in BMP genes. The implications of these variations, investigated using computational analysis and molecular models of the mature TGF-β domain, revealed the impact of modifications on the function of BMP protein. The three-dimensional (3D) structure analysis was performed on the nsSNP Y316S, V386G, E387G, C389G, and C391G nsSNP in the TGF-β domain of chicken BMP2 and H344P, S347P, V357A nsSNP in the TGF-β domain of chicken BMP4 protein that was anticipated to be harmful and of high risk. The ability of the proteins to perform variety of tasks interact with other molecules depends on their tertiary structural composition. The current analysis revealed the four most damaging variants (Y316S, V386G, E387G, C389G, and C391G), highly conserved and functional and are located in the TGF-beta domain of BMP2 and BMP4. The amino acid substitutions E387G, C389G, and C391G are discovered in the binding region. It was observed that the mutations in the TGF-beta domain caused significant changes in its structural organization including the substrate binding sites. Current findings will assist future research focused on the role of these variants in BMP function loss and their role in skeletal disorders, and this will possibly help to develop practical strategies for treating bone-related conditions.

A systematic review on fluoride-induced epigenetic toxicity in mammals

Fluoride, one of the global groundwater contaminants, is ubiquitous in our day-to-day life from various natural and anthropogenic sources. Numerous in vitro, in vivo, and epidemiological studies are conducted to understand the effect of fluoride on biological systems. A low concentration of fluoride is reported to increase oral health, whereas chronic exposure to higher concentrations causes fluoride toxicity (fluorosis). It includes dental fluorosis, skeletal fluorosis, and fluoride toxicity in soft tissues. The mechanism of fluoride toxicity has been reviewed extensively. However, epigenetic regulation in fluoride toxicity has not been reviewed. This systematic review summarizes the current knowledge regarding fluoride-induced epigenetic toxicity in the in vitro, in vivo, and epidemiological studies in mammalian systems. We examined four databases for the association between epigenetics and fluoride exposure. Out of 932 articles (as of 31 March 2022), 39 met our inclusion criteria. Most of the studies focused on different genes, and overall, preliminary evidence for epigenetic regulation of fluoride toxicity was identified. We further highlight the need for epigenome studies rather than candidate genes and provide recommendations for future research. Our results indicate a correlation between fluoride exposure and epigenetic processes. Further studies are warranted to elucidate and confirm the mechanism of epigenetic alterations mediated fluoride toxicity.

Bone morphogenetic protein 2 is a new molecular target linked to non-alcoholic fatty liver disease with potential value as non-invasive screening tool

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease worldwide, being non-alcoholic steatohepatitis (NASH) its most clinically relevant form. Given the risks associated with taking a liver biopsy, the design of accurate non-invasive methods to identify NASH patients is of upmost importance. BMP2 plays a key role in metabolic homeostasis; however, little is known about its involvement in NAFLD onset and progression. This study aimed to elucidate the impact of BMP2 in NAFLD pathophysiology.

METHODS

Hepatic and circulating levels of BMP2 were quantified in serum and liver specimens from 115 biopsy-proven NAFLD patients and 75 subjects with histologically normal liver (NL). In addition, BMP2 content and release was determined in cultured human hepatocytes upon palmitic acid (PA) overload.

RESULTS

We found that BMP2 expression was abnormally increased in livers from NAFLD patients than in subjects with NL and this was reflected in higher serum BMP2 levels. Notably, we observed that PA upregulated BMP2 expression and secretion by human hepatocytes. An algorithm based on serum BMP2 levels and clinically relevant variables to NAFLD showed an AUROC of 0.886 (95%CI, 0.83-0.94) to discriminate NASH. We used this algorithm to develop SAN (Screening Algorithm for NASH): a SAN < 0.2 implied a low risk and a SAN ≥ 0.6 indicated high risk of NASH diagnosis.

CONCLUSION

This proof-of-concept study shows BMP2 as a new molecular target linked to NAFLD and introduces SAN as a simple and efficient algorithm to screen individuals at risk for NASH.

Comparison of rhBMP-2 in Combination with Different Biomaterials for Regeneration in Rat Calvaria Critical-Size Defects

Regeneration of critical bone defects requires the use of biomaterials. The incorporation of osteoinductive agents, such as bone morphogenetic proteins (BMPs), improves bone formation. This study aimed to compare the efficacy of rhBMP-2 in combination with different materials for bone regeneration in critical-sized rat calvarial defects. This was an experimental animal study using 30 rats. In each rat, two 5-mm critical-size defects were made in the calvaria (60 bone defects in total) using a trephine. All rats were randomized to one of the six groups: control (C), autograft + rhBMP-2 (A), absorbable collagen sponge + rhBMP-2 (ACS), β-tricalcium phosphate + rhBMP-2 (B-TCP), bovine xenograft + rhBMP-2 (B), and hydroxyapatite + rhBMP-2 (HA). The outcome was assessed after 4 and 8 weeks using histological description and the histological bone healing scale. Statistical analysis was performed using the Kruskal-Wallis and Mann–Whitney U tests, with a p-value set at 0.05. The average bone healing scores per group were as follows: C group, 12.5; A group, 26.5; ACS group, 18.8; B-TCP group, 26.2; HA group, 20.9; and B group, 20.9. The C group showed a significant difference between weeks 4 and 8 (p = 0.032). Among the 4-week groups, the C group showed a significant difference compared to A (p = 0.001), ACS (p = 0.017), and B-TCP (p = 0.005) groups. The 8-week experimental group did not show any significant differences between the groups. The 5-mm critical size defect in rat calvaria requires the use of bone biomaterials to heal at 4 and 8 weeks. rhBMP-2, as applied in this study, showed no difference in new bone formation when combined with bovine, B-TCP, or HA biomaterials.

Periodontal Tissue as a Biomaterial for Hard-Tissue Regeneration following bmp-2 Gene Transfer

The application of periodontal tissue in regenerative medicine has gained increasing interest since it has a high potential to induce hard-tissue regeneration, and is easy to handle and graft to other areas of the oral cavity or tissues. Additionally, bone morphogenetic protein-2 (BMP-2) has a high potential to induce the differentiation of mesenchymal stem cells into osteogenic cells. We previously developed a system for a gene transfer to the periodontal tissues in animal models. In this study, we aimed to reveal the potential and efficiency of periodontal tissue as a biomaterial for hard-tissue regeneration following a bmp-2 gene transfer. A non-viral expression vector carrying bmp-2 was injected into the palate of the periodontal tissues of Wistar rats, followed by electroporation. The periodontal tissues were analyzed through bone morphometric analyses, including mineral apposition rate (MAR) determination and collagen micro-arrangement, which is a bone quality parameter, before and after a gene transfer. The MAR was significantly higher 3-6 d after the gene transfer than that before the gene transfer. Collagen orientation was normally maintained even after the bmp-2 gene transfer, suggesting that the bmp-2 gene transfer has no adverse effects on bone quality. Our results suggest that periodontal tissue electroporated with bmp-2 could be a novel biomaterial candidate for hard-tissue regeneration therapy.

Upregulated bone morphogenetic protein 5 enhances proliferation and epithelial-mesenchymal transition process in benign prostatic hyperplasia via BMP/Smad signaling pathway

BACKGROUND

Benign prostatic hyperplasia (BPH) is one of the most common illnesses in aging men. Recent studies found that bone morphogenetic protein 5 (BMP5) is upregulated in BPH tissues, however, the role of BMP5 in the development of BPH has not been examined. The current study aims to elucidate the potential roles of BMP5 and related signaling pathways in BPH.

METHODS

Human prostate cell lines (BPH-1, WPMY-1) and human/rat hyperplastic prostate tissues were utilized. Western blot, quantitative real-time polymerase chain reaction, immunofluorescent staining, and immunohistochemical staining were performed. BMP5-silenced and -overexpressed cell models were generated and then cell cycle progression, apoptosis, and proliferation were determined. The epithelial-mesenchymal transition (EMT) was also quantitated. And rescue experiments by BMP/Smad signaling pathway agonist or antagonist were accomplished. Moreover, BPH-related tissue microarray analysis was performed and associations between clinical parameters and expression of BMP5 were analyzed.

RESULTS

Our study demonstrated that BMP5 was upregulated in human and rat hyperplastic tissues and localized both in the epithelial and stromal compartments of the prostate tissues. E-cadherin was downregulated in hyperplastic tissues, while N-cadherin and vimentin were upregulated. Overexpression of BMP5 enhanced cell proliferation and the EMT process via phosphorylation of Smad1/5/8, while knockdown of BMP5 induced cell cycle arrest at G0/G1 phase and blocked the EMT process. Moreover, a BMP/Smad signaling pathway agonist and antagonist reversed the effects of BMP5 silencing and overexpression, respectively. In addition, BMP5 expression positively correlated with prostate volume and total prostate-specific antigen.

CONCLUSION

Our novel data suggest that BMP5 modulated cell proliferation and the EMT process through the BMP/Smad signaling pathway which could contribute to the development of BPH. However, further studies are required to determine the exact mechanism. Our study also indicated that BMP/Smad signaling may be rediscovered as a promising new therapeutic target for the treatment of BPH.

Ectopic Laryngeal Ossification after Bone Morphogenetic Protein-2

We report two cases of ectopic bone formation in the head and neck following treatment with recombinant human bone morphogenetic protein-2 (rhBMP-2). Surgical pathologic data, laryngoscopy imaging, CT imaging, and patient medical history were obtained. First, we report osseous metaplasia in the vocal fold in a 67-year-old male following mandibular dental implants with rhBMP-2; second, a case of severe bony overgrowth of the larynx and fusion to the anterior cervical spine (ACS) in a 73-year-old male following multiple anterior cervical discectomies and fusions with rhBMP-2. Ectopic bone formation following rhBMP-2 has been previously reported. Adverse events like local swelling and edema leading to dysphagia and even airway obstruction after cervical spine application of rhBMP-2 have also been widely reported. Due to the uncommon nature of abnormal bony growth in soft tissue areas of the head and neck and the previously documented adverse effects of rhBMP-2 use, especially in the cervical spine, we consider the two unusual case presentations of ectopic bony formation highly likely to be linked with rhBMP-2. We urge awareness of the adverse effects caused by rhBMP-2, and urge caution in dosing.

Identification, Molecular Characterization, and Tissue Expression Profiles of Three Smad Genes from Water Buffalo (Bubalus bubalis)

Smads are involved in a variety of biological activities by mediating bone morphogenetic protein (BMP) signals. The full-length coding sequences (CDSs) of buffalo Smads 1, 4, and 5 were isolated and identified through RT-PCR in this study. Their lengths are 1398 bp, 1662 bp, and 1398 bp, respectively. In silico analysis showed that their transcriptional region structures, as well as their amino acid sequences, physicochemical characteristics, motifs, conserved domains, and three-dimensional structures of their encoded proteins are highly consistent with their counterparts in the species of Bovidae. The three Smad proteins are all hydrophilic without the signal peptides and transmembrane regions. Each of them has an MH1 domain and an MH2 domain. A nuclear localization sequence was found in the MH1 domain of buffalo Smads 1 and 5. Prediction showed that the function of the three Smads is mainly protein binding, and they can interact with BMPs and their receptors. The three genes were expressed in all 10 buffalo tissues assayed, and their expression in the mammary gland, gonad, and spleen was relatively high. The results here indicate that the three buffalo Smads may be involved in the transcriptional regulation of genes in a variety of tissues.

Participation of Selected Soluble BMP-2 and BMP-7 Bone Morphogenetic Proteins and Their Soluble Type I ALK-1 and Type II BMPR2 Receptors in Formation and Development of Endometriosis

Angiogenesis is considered to be one of the key stages in the development of endometriosis. Recent studies indicate that bone morphogenetic proteins (BMPs) and their receptors (BMPR) may play an important role in the angiogenesis process. In the literature, however, there is a lack of publications concerning binding BMPs and their receptors with the pathogenesis of endometriosis. The aim of the study was to determine the role of soluble bone morphogenetic proteins, BMP-2 and BMP-7, and their receptors, ALK-1 and BMPR2, in the process of the formation and development of endometriosis. Peritoneal fluid was collected in the proliferative phase of the menstrual cycle, from 80 women aged 21-49 years (mean age 31.3 ± 6.7 years) undergoing laparoscopy to determine the causes of primary infertility. The study involved 60 women in the I, II, III, and IV stages of the disease. The reference group consisted of 20 women who did not have endometriosis or other lesions in the pelvic area. The concentration in the peritoneal fluid of women with endometriosis was compared to the concentration of this parameter in the reference group, and a statistically significant reduction in the concentration of the BMP-2 molecule was found, as well as increasing concentrations of BMP-7, ALK-1, and BMPR2. BMP-2 and BMP-7 and their soluble receptors, ALK-1 and BMPR2, are involved in the formation of endometriosis. The changes in the concentrations of most of the tested parameters demonstrated in the study, especially in the early stages of the disease, may indicate the more effective formation of new blood vessels in this period.

Bone Morphogenic Proteins Are Immunoregulatory Cytokines Controlling FOXP3+ Treg Cells

Bone morphogenic proteins (BMPs) are members of the transforming growth factor β (TGF-β) cytokine family promoting differentiation, homeostasis, and self-renewal of multiple tissues. We show that signaling through the bone morphogenic protein receptor 1α (BMPR1α) sustains expression of FOXP3 in T_reg cells in peripheral lymphoid tissues. BMPR1α signaling promotes molecular circuits supporting acquisition and preservation of T_reg cell phenotype and inhibiting differentiation of pro-inflammatory effector Th1/Th17 CD4⁺ T cell. Mechanistically, increased expression of KDM6B (JMJD3) histone demethylase, an antagonist of the polycomb repressive complex 2, underlies lineage-specific changes of T cell phenotypes associated with abrogation of BMPR1α signaling. These results reveal that BMPs are immunoregulatory cytokines mediating maturation and stability of peripheral FOXP3⁺ regulatory T cells (T_reg cells) and controlling generation of iT_reg cells. Thus, we establish that BMPs, a large cytokine family, are an essential link between stromal tissues and the adaptive immune system involved in sustaining tissue homeostasis by promoting immunological tolerance.

Effects of bone morphogenetic proteins on epithelial repair

Epithelial tissue has important functions such as protection, secretion, and sensation. Epithelial damage is involved in various pathological processes. Bone morphogenetic proteins (BMPs) are a class of growth factors with multiple functions. They play important roles in epithelial cells, including in differentiation, proliferation, and migration during the repair of the epithelium. This article reviews the functions and mechanisms of the most profoundly studied BMPs in the process of epithelial damage repair and their clinical significance.

Emerging Roles for Browning of White Adipose Tissue in Prostate Cancer Malignant Behaviour

In addition to its well-known role as an energy repository, adipose tissue is one of the largest endocrine organs in the organism due to its ability to synthesize and release different bioactive molecules. Two main types of adipose tissue have been described, namely white adipose tissue (WAT) with a classical energy storage function, and brown adipose tissue (BAT) with thermogenic activity. The prostate, an exocrine gland present in the reproductive system of most mammals, is surrounded by periprostatic adipose tissue (PPAT) that contributes to maintaining glandular homeostasis in conjunction with other cell types of the microenvironment. In pathological conditions such as the development and progression of prostate cancer, adipose tissue plays a key role through paracrine and endocrine signaling. In this context, the role of WAT has been thoroughly studied. However, the influence of BAT on prostate tumor development and progression is unclear and has received much less attention. This review tries to bring an update on the role of different factors released by WAT which may participate in the initiation, progression and metastasis, as well as to compile the available information on BAT to discuss and open a new field of knowledge about the possible protective role of BAT in prostate cancer.

Strategies to Control or Mimic Growth Factor Activity for Bone, Cartilage, and Osteochondral Tissue Engineering

Growth factors play a critical role in tissue repair and regeneration. However, their clinical success is limited by their low stability, short half-life, and rapid diffusion from the delivery site. Supraphysiological growth factor concentrations are often required to demonstrate efficacy but can lead to adverse reactions, such as inflammatory complications and increased cancer risk. These issues have motivated the development of delivery systems that enable sustained release and controlled presentation of growth factors. This review specifically focuses on bioconjugation strategies to enhance growth factor activity for bone, cartilage, and osteochondral applications. We describe approaches to localize growth factors using noncovalent and covalent methods, bind growth factors via peptides, and mimic growth factor function with mimetic peptide sequences. We also discuss emerging and future directions to control spatiotemporal growth factor delivery to improve functional tissue repair and regeneration.

BMP-4, TGF-β e Smad3 como moduladores da viabilidade das células do líquido sinovial

Objective  Our goal was to evaluate the modulation of the synovial fluid cells (SFC) from patients with and without osteoarthritis (OA) by bone morphogenetic protein 4 (BMP-4), Smad-3 and transforming growth factor beta (TGF-β).

Methods  Synovial fluid was collected from patients submitted to knee arthroscopy or replacement and were centrifuged to isolate cells from the fluid. Cells were cultured for 21 days and characterized as mesenchymal stem cells (MSCs) according to the criteria of the International Society of Cell Therapy. Then, we performed an [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (MTT) assay after exposing cells with and without OA to TGF-β, Smad3 and BMP-4 pathway inhibitors and to different concentrations of BMP4.

Results  Exposure to the TGF-β, Smad3 and BMP-4 inhibitors modifies the mitochondrial activity of the SFCs. The activity of the SFCs is modified by influences of increasing concentrations of BMP4, but there is no difference in cellular activity between patients with and without OA.

Conclusion  TGF-β, Smad3 and BMP-4 modulate the activity of SFCs from patients with and without knee OA.

Adipose tissue plasticity and the pleiotropic roles of BMP signaling

Adipose tissues, including white, beige, and brown adipose tissue, have evolved to be highly dynamic organs. Adipose tissues undergo profound changes during development and regeneration and readily undergo remodeling to meet the demands of an everchanging metabolic landscape. The dynamics are determined by the high plasticity of adipose tissues, which contain various cell types: adipocytes, immune cells, endothelial cells, nerves, and fibroblasts. There are numerous proteins that participate in regulating the plasticity of adipose tissues. Among these, bone morphogenetic proteins (BMPs) were initially found to regulate the differentiation of adipocytes, and they are being reported to have pleiotropic functions by emerging studies. Here, in the first half of the article, we summarize the plasticity of adipocytes and macrophages, which are two groups of cells targeted by BMP signaling in adipose tissues. We then review how BMPs regulate the differentiation, death, and lipid metabolism of adipocytes. In addition, the potential role of BMPs in regulating adipose tissue macrophages is considered. Finally, the expression of BMPs in adipose tissues and their metabolic relevance are discussed.

Platelet microparticles load a repertory of miRNAs programmed to drive osteogenic phenotype

Autologous platelet-rich plasma accelerates bone healing by releasing biomolecules during their degranulation process, which are transported by vesicle-like structures called platelet microparticles (PMPs). However, the underlying mechanisms regulating the osteogenic differentiation by PMP-released miRs remain poorly understood and this prompted us to better address this issue. Thus, miRNAseq expression profiles (E-GEOD-76789) were downloaded from ArrayExpress database. GEO2R was performed to evaluate the differential expression, and mirnatap R package was used to find targets for differentially expressed miRNAs. An extend protein-protein (ePPI) network for osteogenic marker proteins was generated using String, and DAVID tools were used to perform gene ontology and KEGG pathway analysis from ePPI and miRNAs targets. Our data show that ePPI network was composed by 232 nodes and 2,175 edges, with a clustering coefficient of 0.546. MCODE was able to identify seven clusters contained in the ePPI network, and the two that presented a score above 10 were used in further analysis. Conversely, 15,944 different targets were found as down-expressed while 5,715 different targets were up-expressed. Among the downregulated 75 miRNAs, 70 have predicted targets present in the ePPI network, while the 21 upregulated miRNAs have 19 predicted targets in the ePPI network. Our study provides a registry of miRNAs that play a central role in regulating osteogenic phenotype, which might have potential therapeutic applications in bone regeneration and bone tissue engineering.

A new glioma grading model based on histopathology and Bone Morphogenetic Protein 2 mRNA expression

Glioma, the most common form of primary malignant brain tumors, is graded based solely on histopathological appearance, which has led to prognostic discrepancies. This study aimed to establish a new glioma grading model by analyzing the expression of Bone Morphogenetic Protein 2 (BMP2) mRNA in patients with gliomas as well, named the Histopathological-BMP2 (HB) system. Clinical information was collected from 692 patients from the Chinese Glioma Genome Atlas database. According to pathological glioma subtypes and the expression of BMP2 mRNA in tumor tissues, the new subtypes HBs, HBh, HBm and HB1 were established, with BMP2 expression highest in HBs and lowest in HB1. Survival periods were analyzed. Based on this, the expression of three BMP2 receptors (BMPR1A, BMPR1B, and BMPR2) was also analyzed, which was related to the prognosis of patients. This new classification model was validated in further groups of patients from the CGGA database (n = 291) and the Cancer Genome Atlas (n = 625). A new glioma grade (HB grade) based on histopathology and BMP2 expression can predict the prognosis of glioma patients, with BMPR1B and BMPR2 expression indicating a different prognosis in different types of gliomas. The higher the concentration of BMP2, the better the prognosis of patients.

TNF‑α regulates the osteogenic differentiation of bone morphogenetic factor 9 adenovirus‑transduced rat follicle stem cells via Wnt signaling

Periodontitis is a chronic infectious disease that alters the cellular microenvironment and promotes bone absorption. Bone morphogenetic protein 9 (BMP9) serves an important role in proliferation and differentiation, and tumor necrosis factor‑alpha (TNF‑α) is an important contributor to bone resorption. The present study aimed to investigate the effect of osteogenic differentiation in the presence of BMP9 and TNF‑α in rat follicle stem cells (rDFCs). rDFCs were transfected with adenoviruses expressing BMP9 (AdBMP9) and the expression levels of important proteins [BMP9, β‑catenin, glycogen synthase kinase 3β (GSK3β), phosphorylated‑GSK3β, calcium/calmodulin dependent protein kinase II and nemo like kinase] were determined using western blotting. The effect of osteogenesis was analyzed using reverse transcription‑quantitative PCR, in addition to alkaline phosphatase, Alizarin Red S, and hematoxylin and eosin staining methods. The results of the present study revealed that TNF‑α activated the canonical Wnt signaling pathway and suppressed osteogenesis. High concentrations of Dickkopf 1 (DKK1) reduced the osteogenic differentiation of AdBMP9‑transduced rDFCs, whereas low concentrations of DKK1 promoted BMP9‑induced bone formation, which was discovered to partially act via the canonical and non‑canonical Wnt signaling pathways. In conclusion, the findings of the present study suggested that the enhanced promoting effect of BMP9 alongside the treatment with low concentrations of DKK1 may be useful for treating periodontitis bone absorption.

Deficiency in Aim2 affects viability and calcification of vascular smooth muscle cells from murine aortas and angiotensin-II induced aortic aneurysms

Background

Phenotypic transformation of vascular smooth muscle cells is a key element in vascular remodeling and aortic aneurysm growth. Previously, deletion of several inflammasome components decreased formation of aortic aneurysm (AA) in the Angiotensin II (AngII) -induced mouse model. We hypothesized that the inflammasome sensor Absent in melanoma 2 (Aim2) might affect the phenotype of vascular smooth muscle cells (VSMC), thereby reducing AA formation.

Methods

Aim2−/− mice and wild-type (WT) C57Bl/6 J mice were used as an animal model. VSMC were isolated from 6 months old mice and grown in vitro. Young (passage 3–5) and senescent (passage 7–12) cells were analyzed in vitro for calcification in mineralization medium by Alizarin Red S staining. Expression of calcification and inflammatory markers were studied by real-time RT-PCR and Western blotting, release of cytokines was determined by ELISA. To induce AA, osmotic mini-pumps loaded with AngII (1500 ng/kg bodyweight/min) were implanted for 28 days in male mice at 6 months of age.

Results

Compared with VSMC from WT mice, VSMC isolated from Aim2−/− mice were larger, less viable, and underwent stronger calcification in mineralization medium, along with induction of Bmp4 and repression of Tnfsf11/Rankl gene expression. In addition, Aim2 deficiency was associated with reduced inflammasome gene expression and release of Interleukin-6. Using the mouse model of AngII induced AA, Aim2 deficiency reduced AA incidence to 48.4% (15/31) in Aim2−/− mice versus 76.5% (13/17) in WT mice. In contrast to Aim2−/− mice, AA from WT mice expressed significantly increased levels of alpha-smooth muscle actin/Acta2, indicating tissue remodeling. Reduced cell proliferation in Aim2−/− mice was indicated by significantly increased p16ink4a/Cdkn2a expression in untreated and AngII-infused aortas, and by significantly lower amounts of proliferating (Ki67 positive) VSMC in AngII-infused Aim2−/− mice.

Conclusions

Our results suggest a role for Aim2 in regulating VSMC proliferation and transition to an osteoblast-like or osteoclast-like phenotype, thereby modulating the response of VSMC in aortic remodeling and AA formation.

Anti‑proliferative effect of honokiol on SW620 cells through upregulating BMP7 expression via the TGF‑β1/p53 signaling pathway

Honokiol (HNK), a natural pharmaceutically active component extracted from magnolia bark, has been used for clinical treatments and has anti‑inflammatory, antiviral and antioxidative effects. In recent years, anticancer research has become a major hotspot. However, the underlying molecular mechanisms of how HNK inhibits colorectal cancer have remained elusive. The present study focused on elucidating the effects of HNK on the expression of bone morphogenetic protein (BMP)7 and its downstream interaction with transforming growth factor (TGF)‑β1 and p53 in colon cancer. In in vitro assays, cell viability, cell cycle distribution and apoptosis were examined using Cell Counting Kit‑8, flow cytometry and reverse transcription‑quantitative PCR, respectively. In addition, the expression of BMP7, TGF‑β1 and relevant signaling proteins was determined by western blot analysis. In vivo, the anticancer effect of HNK was assessed in xenografts in nude mice. Furthermore, immunohistochemistry was performed to evaluate the association between BMP7 and TGF‑β1 expression in colon cancer. The results indicated that HNK inhibited the proliferation of colon cancer cell lines, with SW620 cells being more sensitive than other colon cancer cell lines. Furthermore, HNK markedly promoted the expression of BMP7 at the mRNA and protein level. Exogenous BMP7 potentiated the effect of HNK on SW620 cells, while knocking down BMP7 inhibited it. As a downstream mechanism, HNK increased the expression of TGF‑β1 and p53, which was enhanced by exogenous BMP7 in SW620 cells. In addition, immunohistochemical analysis indicated a positive association between BMP7 and TGF‑β1 expression. Hence, the present results suggested that HNK is a promising agent for the treatment of colon cancer and enhanced the expression TGF‑β1 and p53 through stimulating BMP7 activity via the non‑canonical TGF‑β signaling pathway.

Colorectal Cancer and Bone Tissue: Fantastic Relations and Where to Find Them

Colorectal cancer (CRC) is the third most common cancer worldwide. There is a need for the early diagnosis of CRC for a better prognostic outcome. It is, therefore, crucial to understand the CRC pathogenesis in all its aspects. In many cases, one of the main causes of cancer-related deaths is the presence of metastases. In this context, an often overlooked aspect is the metastatic tropism, since CRC, like other cancers, is more prone to metastasize some organs rather than others. Beyond the liver and lung, and differently from other types of cancers, a not usual site of CRC metastases is the bone. However, it may assume a crucial role in the development and the outcome of the disease. Therefore, this review aims to discuss the complex relations between bone markers and CRC pathogenesis, suggesting the use of these molecules as potential targets for therapeutic purposes. Different osteogenic molecules, some of whom are growth factors and are implicated in the different osteogenic pathways, have been proved to also be involved in CRC progression. Some of them are oncogenes, while others oncosuppressors, and in a future perspective, some of them may represent new potential CRC biomarkers.