Bone Morphogenetic Protein Cytokines Research Articles

Effect of modified compound calcium phosphate cement on the differentiation and osteogenesis of bone mesenchymal stem cells

BackgroundThe aim of this study is to evaluate the effect of self-invented compound calcium phosphate cement upon the proliferation and osteogenesis of bone mesenchymal stem cells (BMSCs).MethodsFour groups including traditional calcium phosphate cement, modified calcium phosphate cement, modified calcium phosphate cement plus bone morphogenetic protein (BMP), and control groups were established. The cell proliferation curve was delineated by MTT. The activity of BMSCs to synthesize alkaline phosphatase (AKP) was evaluated. The growth and invasion of BMSCs were observed. The expression levels of aggrecan, collagen I, collagen II, AKP, and OSX messenger RNA (mRNA) were measured by using RT-PCR.ResultsCompared with other groups, the BMSCs in the modified calcium phosphate cement group presented with loose microstructure and the BMSCs closely attached to the vector margin. At 7 days after co-culture, the expression of AKP in the modified calcium phosphate cement plus BMP group was significantly upregulated compared with those in other groups. In the modified calcium phosphate cement group, the BMSCs properly proliferated on the surface of bone cement and invaded into the cement space. At 10 days, the expression levels of aggrecan, collagen I, collagen II, AKP, and OSX mRNA in the modified calcium phosphate cement and modified calcium phosphate cement plus BMP groups were significantly upregulated than those in other groups.ConclusionsModified compound calcium phosphate cement possesses excellent biocompatibility and osteogenic induction ability. Loose microstructure and large pore size create a favorable environment for BMSCs proliferation and vascular invasion, as an ideal vector for releasing BMP cytokines to mediate the differentiation and osteogenesis of BMSCs.

Serum concentration of bone morphogenetic proteins (BMPs) is not linked to serum anti-mullerian hormone (AMH) level

Serum concentration of anti-mullerian hormone (AMH) is used as a biomarker in practical clinics. As bone morphogenetic protein (BMP) cytokines induce AMH expression in human granulosa cells (GC) in vitro, serum concentrations of BMP cytokines and AMH were evaluated whether there would be a relationship between BMP cytokines and AMH. Serum concentrations of BMP-2, -6 -7, AMH and FSH were measured in 25 infertility patients using EIA or ELISA kits. Among 25 infertile patients, serum BMP-2, -6, and -7 were detected only in 10, 3, 7 patients respectively, while AMH was detected in 24 out of 25 patients. There was no relation between BMP cytokines and AMH concentration in serum. The detection rate of these BMPs in serum was much lower than that of AMH. Serum concentration of BMP-2, -6, -7 could not estimate serum AMH level.

Snail depletes the tumorigenic potential of glioblastoma

Glioblastoma multiforme (GBM) is an aggressive brain malignancy characterized by high heterogeneity and invasiveness. It is increasingly accepted that the refractory feature of GBM to current therapies stems from the existence of few tumorigenic cells that sustain tumor growth and spreading, the so-called glioma-initiating cells (GICs). Previous studies showed that cytokines of the bone morphogenetic protein (BMP) family induce differentiation of the GICs, and thus act as tumor suppressors. Molecular pathways that explain this behavior of BMP cytokines remain largely elusive. Here, we show that BMP signaling induces Smad-dependent expression of the transcriptional regulator Snail in a rapid and sustained manner. Consistent with its already established promigratory function in other cell types, we report that Snail silencing decreases GBM cell migration. Consequently, overexpression of Snail increases GBM invasiveness in a mouse xenograft model. Surprisingly, we found that Snail depletes the GBM capacity to form gliomaspheres in vitro and to grow tumors in vivo, both of which are important features shared by GICs. Thus Snail, acting downstream of BMP signaling, dissociates the invasive capacity of GBM cells from their tumorigenic potential.

The Localization and Regulation of Proprotein Convertase Subtilisin/Kexin (PCSK) 6 in Human Ovary

The aim of this study is to evaluate the expression and regulation of proprotein convertase subtilisin/kexin (PCSK) 6, which is known to be an important factor in the production of bone morphogenetic protein (BMP) cytokines in human ovary. The localization of PCSK 6 protein in normal human ovaries was examined by immunohistochemistry. Human granulosa cells (GC), obtained from 34 patients undergoing ovarian stimulation for in vitro fertilization, were cultured with BMP-2, BMP-6, BMP-7, BMP-15, growth differentiation factor (GDF)-9, and activin-A with or without FSH. PCSK 6 mRNA expression level was evaluated by quantitative real-time reverse transcription and polymerase chain reaction (RT-PCR). An immunohistochemistry study revealed that GC expressed PCSK 6 throughout follicular development, beginning in the primary follicle stage, while oocytes expressed PCSK 6 from the primordial follicle stage onwards. An in vitro study demonstrated that BMP-2, BMP-6, BMP-7, and BMP-15, not activin-A and GDF-9, decreased PCSK 6 gene expression in human GC. FSH induced PCSK 6 mRNA in the presence of activin-A or GDF-9. GDF-3, which is an inhibitor of BMP cytokines, also induced PCSK 6 mRNA expression. PCSK 6, which is a critical factor to produce BMP cytokines, was suppressed with BMP stimulation in human GC, suggesting the presence of a negative feedback system in the follicular development process.

Growth differentiation factor 3 is induced by bone morphogenetic protein 6 (BMP-6) and BMP-7 and increases luteinizing hormone receptor messenger RNA expression in human granulosa cells

To examine the relevance of growth differentiation factor 3 (GDF-3) and bone morphogenetic protein (BMP) cytokines in human ovary. Molecular studies. Research laboratory. Eight women undergoing salpingo-oophorectomy and 30 women undergoing ovarian stimulation for invitro fertilization. Localizing GDF-3 protein in human ovaries; granulosa cells (GC) cultured with GDF-3, BMP-6, or BMP-7 followed by RNA extraction. The localization of GDF-3 protein in normal human ovaries via immunohistochemical analysis, GDF-3 messenger RNA (mRNA) expression evaluation via quantitative real-time reverse transcription and polymerase chain reaction (RT-PCR), and evaluation of the effect of GDF-3 on leuteinizing hormone (LH) receptor mRNA expression via quantitative real-time RT-PCR. In the ovary, BMP cytokines, of the transforming growth factor beta (TGF-β) superfamily, are known as a luteinization inhibitor by suppressing LH receptor expression in GC. Growth differentiation factor 3, a TGF-β superfamily cytokine, is recognized as an inhibitor of BMP cytokines in other cells. Immunohistochemical analysis showed that GDF-3 was strongly detected in the GC of antral follicles. An invitro assay revealed that BMP-6 or BMP-7 induced GDF-3 mRNA in GC. Also, GDF-3 increased LH receptor mRNA expression and inhibited the effect of BMP-7, which suppressed the LH receptor mRNA expression in GC. GDF-3, induced with BMP-6 and BMP-7, might play a role in folliculogenesis by inhibiting the effect of BMP cytokines.

Bone morphogenetic protein–2 activity is regulated by secreted phosphoprotein–24 kd, an extracellular pseudoreceptor, the gene for which maps to a region of the human genome important for bone quality

The material properties of bone are the sum of the complex and interrelated anabolic and catabolic processes that modulate formation and turnover. The 2q33-37 region of the human genome contains quantitative trait loci important in determining the broadband ultrasound attenuation (an index of trabecular microarchitecture, bone elasticity, and susceptibility to fracture) of the calcaneus, but no genes of significance to bone metabolism have been identified in this domain. Secreted phosphoprotein–24 kd ( SPP24 or SPP2) is a novel and relatively poorly characterized growth hormone–regulated gene that maps to 2q37. The purpose of this review is to summarize the status of research related to spp24 and how it regulates bone morphogenetic protein (BMP) bioactivity in bone. SPP24 codes for an extracellular matrix protein that contains a high-affinity BMP-2–binding transforming growth factor– β receptor II homology 1 loop similar to those identified in fetuin and the receptor itself. SPP24 is transcribed primarily in the liver and bone. High levels of spp24 (a hydroxyapatite-binding protein) are found in bone, and small amounts are found in fetuin-mineral complexes. Full-length secretory spp24 inhibits ectopic bone formation, and overexpression of spp24 reduces murine bone mass and density. Spp24 is extremely labile to proteolysis, a process that regulates its bioactivity in vivo. For example, an 18.5-kd degradation product of spp24, designated spp18.5, is pro-osteogenic. A synthetic cyclized Cys 1-to-Cys 19 disulfide-bonded peptide (BMP binding peptide) corresponding to the transforming growth factor– β receptor II homology 1 domain of spp24 and spp18.5 binds BMP-2 and increases the rate and magnitude of BMP-2–mediated ectopic bone formation. Thus, the mechanism of action of spp18.5 and spp24 may be to regulate the local bioavailability of BMP cytokines. SPP24 is regulated by growth hormone and 3 major families of transcription factors (nuclear factor of activated T cells, CCAAT/enhancer-binding protein, Cut/Cux/CCAAT displacement protein) that regulate mesenchymal cell proliferation, embryonic patterning, and terminal differentiation. The gene contains at least 2 single nucleotide polymorphisms. Given its mechanism of action and sequence variability, SPP24 may be an interesting candidate for future studies of the genetic regulation of bone mass, particularly during periods of BMP-mediated endochondral bone growth, development, and fracture healing.

Bone morphogenetic protein (BMP)-responsive elements located in the proximal and distal hepcidin promoter are critical for its response to HJV/BMP/SMAD

The hemochromatosis proteins HFE, transferrin receptor 2 (TfR2) and hemojuvelin (HJV, HFE2) positively control expression of the major iron regulatory hormone hepcidin. HJV is a bone morphogenetic protein (BMP) co-receptor that enhances the cellular response to BMP cytokines via the phosphorylation of SMAD proteins. In this study, we show that two highly conserved and sequence-identical BMP-responsive elements located at positions -84/-79 (BMP-RE1) and -2,255/-2,250 (BMP-RE2) of the human hepcidin promoter are critical for both the basal hepcidin mRNA expression and the hepcidin response to BMP-2 and BMP-6. While BMP-RE1 and BMP-RE2 show additive effects in responding to HJV-mediated BMP signals, only BMP-RE1 that is located in close proximity to a previously identified STAT-binding site is important for the hepcidin response to IL-6. These data identify a missing link between the HJV/BMP signaling pathways and hepcidin transcription, and further define the connection between inflammation and BMP-dependent hepcidin promoter activation. As such, they provide important new information furthering our understanding of disorders of iron metabolism and the anemia of inflammation.

Fetuin inhibition of heterotopic ossification in vitro

Introduction: Heterotopic bone or ossification (HO) refers to the formation of osseous tissue at a location other than where it would normally be found, and can also be referred to as being ectopic bone. Fully differentiated osseous tissue forms at a location where bone was not meant to be. When such bone forms in following total or sub-total joint replacement surgery, a variety of complications can occur including dramatic reductions in joint function leading to marked restriction of movement to complete ankylosis (ie, total loss of movement). Small case series have demonstrated that HO may develop in as many as 35% of TMJ reconstruction cases. Although the pathophysiology of HO is not well understood, it has been suggested that primitive mesenchymal cells near surgical sites where bone surgery may have been done are exposed to residual bone dust, the latter containing bone morphogenetic proteins (BMP), cytokines that induce osteodifferentiation in mesenchymal cells hence leading to osteogenesis. Fetuin, also known as a2HS-glycoprotein (Ahsg), is a serum and bone resident glycoprotein, which binds TGFb and BMP cytokines due to the fact that it has a BMP/TGFb receptor-like region within its structure. Ahsg inhibits TGFb-induced in vitro osteogenesis, most likely by acting as a decoy receptor for TGFb and BMP. Given this, we hypothesized that fetuin would inhibit BMP mediated effects in cell culture and ultimately in vivo.