Bone morphogenetic protein is required for fibroblast growth factor 2-dependent later-stage osteoblastic differentiation in cranial suture cells

Background: Understanding the pathophysiological process of calvarial bones development is important for the treatments on relative diseases such as craniosynostosis. While, the role of fibroblast growth factor (FGF) and bone morphogenetic protein (BMP) and how they interacted in osteoblast differentiation remain unclear. Methods: we digested bone fragments around the coronal and sagittal sutures from newborn rats to harvest suture cells. Markers expression at different osteoblast differentiation stage was analyzed by increasing FGF2 concentration and BMP2 blocking in these cells. Results: BMP2 expression could be stimulated by FGF2 in a dose and time dependent manner. FGF2 stimulation may decrease early marker of osteoblast differentiation (collagen type-1, COL-1) and increase the expression of continuously-expressed or late markers (alkaline phosphatase, ALP; osteocalcin, OC and bone sialoprotein, BSP) to accelerate mineralization. Inhibition of BMP2 signaling by Noggin weakens the effect of FGF2 on induction of later-stage osteoblastic differentiation of cranial suture cells. Conclusion: Our data suggest that BMP2 signaling is required for FGF2-dependent induction of later-stage of cranial suture cell osteoblastic differentiation.     

Bone morphogenetic protein 4 inhibits liposaccharide‐induced inflammation in the airway

Bone morphogenetic protein 4 (BMP4) is a multifunctional growth factor that belongs to the TGF‐β superfamily. The role of BMP4 in lung diseases is not fully understood. Here, we demonstrate that BMP4 was upregulated in lungs undergoing lipopolysaccharide (LPS)‐induced inflammation, and in airway epithelial cells treated with LPS or TNF‐α. BMP4 mutant (BMP4^+/?) mice presented with more severe lung inflammation in response to LPS or Pseudomonas aeruginosa, and lower bacterial load compared with that in BMP4^+/+ mice. Knockdown of BMP4 by siRNA increased LPS and TNF‐α‐induced IL‐8 expression in 16HBE human airway epithelial cells and in primary human bronchial epithelial cells. Similarly, peritoneal macrophages from BMP4^+/? mice produced greater levels of TNF‐α and keratinocyte chemoattractant (KC) upon LPS treatment compared with cells from BMP4^+/+ mice. Administration of exogenous BMP4 attenuated the upregulation of TNF‐α, IL‐8, or KC induced by LPS and/or TNF‐α in airway epithelial cells, and peritoneal macrophages. Finally, partial deficiency of BMP4 in BMP4^+/? mice protected the animals from restrictive lung function reduction upon chronic LPS exposure. These results indicate that BMP4 plays an important anti‐inflammatory role, controlling the strength and facilitating the resolution of acute lung inflammation; yet, BMP4 also contributes to lung function impairment during chronic lung inflammation.     

Functional analysis of CTRP3/cartducin in Meckel's cartilage and developing condylar cartilage in the fetal mouse mandible

CTRP3/cartducin, a novel C1q family protein, is expressed in proliferating chondrocytes in the growth plate and has an important role in regulating the growth of both chondrogenic precursors and chondrocytes in vitro. We examined the expression of CTRP3/cartducin mRNA in Meckel's cartilage and in condylar cartilage of the fetal mouse mandible. Based on in situ hybridization studies, CTRP3/cartducin mRNA was not expressed in the anlagen of Meckel's cartilage at embryonic day (E)11.5, but it was strongly expressed in Meckel's cartilage at E14.0, and then reduced in the hypertrophic chondrocytes at E16.0. CTRP3/cartducin mRNA was not expressed in the condylar anlagen at E14.0, but was expressed in the upper part of newly formed condylar cartilage at E15.0. At E16.0, CTRP3/cartducin mRNA was expressed from the polymorphic cell zone to the upper part of the hypertrophic cell zone, but was reduced in the lower part of the hypertrophic cell zone. CTRP3/cartducin-antisense oligodeoxynucleotide (AS-ODN) treatment of Meckel's cartilage and condylar anlagen from E14.0 using an organ culture system indicated that, after 4-day culture, CTRP3/cartducin abrogation induced curvature deformation of Meckel's cartilage with loss of the perichondrium and new cartilage formation. Aggrecan, type I collagen, and tenascin-C were simultaneously immunostained in this newly formed cartilage, indicating possible transformation from the perichondrium into cartilage. Further, addition of recombinant mouse CTRP3/cartducin protein to the organ culture medium with AS-ODN tended to reverse the deformation. These results suggest a novel function for CTRP3/cartducin in maintaining the perichondrium. Moreover, AS-ODN induced a deformation of the shape, loss of the perichondrium/fibrous cell zone, and disorder of the distinct architecture of zones in the mandibular condylar cartilage. Additionally, AS-ODN-treated condylar cartilage showed reduced levels of mRNA expression of aggrecan, collagen types I and X, and reduced BrdU-incorporation. These results suggest that CTRP3/cartducin is not only involved in the proliferation and differentiation of chondrocytes, but also contributes to the regulation of mandibular condylar cartilage.     

Bone development in the femoral epiphysis of mice: the role of cartilage canals and the fate of resting chondrocytes.

In mammals, the exact role of cartilage canals is still under discussion. Therefore, we studied their development in the distal femoral epiphysis of mice to define the importance of these canals. Various approaches were performed to examine the histological, cellular, and molecular events leading to bone formation. Cartilage canals started off as invaginations of the perichondrium at day (D) 5 after birth. At D 10, several small ossification nuclei originated around the canal branched endings. Finally, these nuclei coalesced and at D 18 a large secondary ossification centre (SOC) occupied the whole epiphysis. Cartilage canal cells expressed type I collagen, a major bone-relevant protein. During canal formation, several resting chondrocytes immediately around the canals were active caspase 3 positive but others were freed into the canal cavity and appeared to remain viable. We suggest that cartilage canal cells belong to the bone lineage and, hence, they contribute to the formation of the bony epiphysis. Several resting chondrocytes are assigned to die but others, after freeing into the canal cavity, may differentiate into osteoblasts.     

Effect of bone morphogenetic protein signaling on development of the jaw skeleton

Bone morphogenetic proteins (BMPs) regulate many aspects of development including skeletogenesis. Here, we examined the response of neural crest‐derived cells to ectopic BMP signaling by infecting avian embryos with retroviruses encoding Bmp‐2 or Bmp‐4 at various times of development. Infection at stages 10 and 15 transformed large areas of the skull into cartilage by day 13. At this time cartilage condensations were still forming, which revealed the presence of uncommitted mesenchymal cells. By day 19, hypertrophic chondrocytes were present in the cartilage possibly due to changes in the perichondrium that relieved repression on hypertrophy. While these cells expressed Sox9, Collagen‐2, Runx2, Ihh, Noggin, and Collagen‐10, cartilage was not replaced by bone. Whether this is an intrinsic property of the skull cartilage, or results from sustained Bmp signaling is not known. Developmental Dynamics 237:3727–3737, 2008. © 2008 Wiley‐Liss, Inc.     

N,N-dicarboxymethyl chitosan as delivery agent for bone morphogenetic protein in the repair of articular cartilage

Bone morphogenetic protein (BMP), associated with N,N-dicarboxymethyl chitosan, is used to induce or facilitate the repair of articular cartilage lesions. This association is intended for the synergistic potentiation of the respective biological effects. Data show that BMP-7 enhances the in vivo proliferation of cells with chondrocytes phenotype in the articular environment, leading to partial healing of the articular surface of the lesions. N,N-dicarboxymethyl chitosan is found to be useful as a molecular carrier or drug delivery agent.     

Molecular studies on the roles of Runx2 and Twist1 in regulating FGF signaling

Background: Supernumerary teeth are often observed in patients suffering from cleidocranial dysplasia due to a mutation in Runx2 that results in haploinsufficiency. However, the underlying molecular mechanisms are poorly defined. In this study, we assessed the roles of Runx2 and its functional antagonist Twist1 in regulating fibroblast growth factor (FGF) signaling using in vitro biochemical approaches. Results: We showed that Twist1 stimulated Fgfr2 and Fgf10 expression in a mesenchymal cell line and that it formed heterodimers with ubiquitously expressed E12 (together with E47 encoded by E2A gene) and upregulated Fgfr2 and Fgf10 promoter activities in a dental mesenchyme‐derived cell line. We further demonstrated that the bHLH domain of Twist1 was essential for its synergistic activation of Fgfr2 promoter with E12 and that the binding of E12 stabilized Twist1 by preventing it from undergoing lysosomal degradation. Although Runx2 had no apparent effects on Fgfr2 and Fgf10 promoter activities, it inhibited the stimulatory activity of Twist1 on Fgfr2 promoter. Conclusions: These findings suggest that Runx2 haploinsufficiency might result in excessive unbound Twist1 that can freely bind to E12 and enhance FGF signaling, thereby promoting the formation of extra teeth. Developmental Dynamics 241:1708–1715, 2012. © 2012 Wiley Periodicals, Inc.     

Bone morphogenetic protein 9: a potent modulator of cartilage development in vitro

Few publications describe the activity of bone morphogenetic protein-9 (BMP-9), but the consensus of these largely in vivo studies is that while BMP-9 can induce ectopic bone formation at relatively large concentrations, it is primarily active in non-skeletal locations--including the liver, nervous system and marrow. To study the effects of BMP-9 on chondrogenesis in a well-defined environment, calf articular chondrocytes were seeded onto biodegradable PGA scaffolds. The resulting cell-polymer constructs were cultured in either control medium or medium supplemented with 1, 10, 50 or 100 ng/ml of BMP-9. After 4 weeks of in vitro culture, all concentrations of BMP-9 increased the total mass of the constructs, and the amounts of collagen, glycosaminoglycans (GAG) and cells per construct. On a mass percentage basis, BMP-9 tended to increase GAG, to decrease the relative amount of collagen and had little effect on the relative amount of cells. BMP-9 elicited qualitatively similar responses as BMP-2, -12 and -13. However, in contrast to BMP-12 and -13, BMP-9 (at concentrations > or = 10 ng/ml) induced hypertrophic chondrocyte formation and was the only BMP tested to induce mineralization. Taken together, these data suggest that BMP-9 is a potent modulator of cartilage development in vitro.     

骨形态蛋白2体外诱导大鼠骨髓间充质干细胞分化为心肌样细胞

目的 应用骨形态蛋白2(BMP-2)体外诱导骨髓间充质干细胞(MSCs)向心肌样细胞分化,探索MSCs向心肌细胞分化的诱导方法.方法 取SD大鼠四肢骨骨髓,分离培养MSCs,应用BMP-2定向诱导,相差显微镜观察细胞形态学变化,应用免疫细胞化学、激光扫描共焦显微镜技术检测结蛋白(desmin)、α-横纹肌肌动蛋白(α-sareomeric actin)、心肌特异性肌钙蛋白(C-TnT)的表达,透射电镜鉴定.在诱导后7d、21d和28d 3个时间点以半定量RT-PCR方法检测细胞心肌早期转录因子(GATA4)和心肌特异性α-肌凝蛋白重链(α-MHC)的表达.结果 BMP-2诱导后的MSCs细胞伸出伪足,排列方向渐趋一致.MSCs体外经BMP-2诱导后分化的细胞结蛋白、α-横纹肌肌动蛋白、C-TnT均表达阳性,结蛋白、α-横级肌肌动蛋白阳性率较高,分别为37.28%和63.94%,而C-TnT阳性率较低为34.66%.透射电镜下可见到平行排列的肌丝,大量的粗面内质网和线粒体,富含糖原和核糖体.RT-PCR结果显示,GATA4于诱导后7d弱表达,21d表达增强,28d表达减弱.α-MHC在诱导后7d不表达,21d弱表达,28d表达明显.结论骨髓间充质干细胞在BMP-2诱导下可定向分化为心肌样细胞,是自体心肌细胞的一种良好供体来源.     

An in situ hybridization study of the Syndecan family in the developing condylar cartilage of fetal mouse mandible

Mandibular condylar cartilage is a representative secondary cartilage, differing from primary cartilage in various ways. Syndecan is a cell-surface heparan sulfate proteoglycan and speculated to be involved in chondrogenesis and osteogenesis. This study aimed to investigate the expression patterns of the syndecan family in the developing mouse mandibular condylar cartilage. At embryonic day (E)13.0 and E14.0, syndecan-1 and -2 mRNAs were expressed in the mesenchymal cell condensation of the condylar anlage. When condylar cartilage was formed at E15.0, syndecan-1 mRNA was expressed in the embryonic zone, wherein the mesenchymal cell condensation is located. Syndecan-2 mRNA was mainly expressed in the perichondrium. At E16.0, syndecan-1 was expressed from fibrous to flattened cell zones and syndecans-2 was expressed in the lower hypertrophic cell zone. Syndecan-3 mRNA was expressed in the condylar anlage at E13.0 and E13.5 but was not expressed in the condylar cartilage at E15.0. It was later expressed in the lower hypertrophic cell zone at E16.0. Syndecan-4 mRNA was expressed in the condylar anlage at E14.0 and the condylar cartilage at E15.0 and E16.0. These findings indicated that syndecans-1 and -2 could be involved in the formation from mesenchymal cell condensation to condylar cartilage. The different expression patterns of the syndecan family in the condylar and limb bud cartilage suggest the functional heterogeneity of chondrocytes in the primary and secondary cartilage.     

Runx3蛋白在胃癌中的表达及其临床病理学意义

目的 探讨新型抑癌基因Runx3蛋白表达与胃腺癌发生、发展、临床病理特征及患者预后之间的关系.方法 用免疫组织化学SP法,检测63例胃腺癌组织、19例胃黏膜不典型增生组织及10例因胃良性病变行部分切除的正常胃黏膜组织中Runx3蛋白的表达.结果 (1) Runx3蛋白在胃癌中阳性表达率为39.7%,明显低于胃黏膜不典型增生组织68.4%及正常胃黏膜组织90%,差异具有统计学意义(P＜0.05).(2) Runx3蛋白阳性表达与胃癌组织病理分级、浸润深度、淋巴结转移有关,而与患者的年龄、性别、大小及临床分期无关.(3) Runx3蛋白表达阳性者的生存率高于表达阴性者的生存率(P＜0.05).Runx3蛋白阳性者,术后生存时间长.结论 Runx3蛋白对胃癌的发生发展起重要作用,是评估胃癌患者预后的一项重要指标.     

Linkage between stature and a region on chromosome 20 and analysis of a candidate gene,bone morphogenetic protein 2

Sib-pair linkage analysis of the quantitative trait, stature, in over 500 Pima Indians indicates that a genetic determinant of governing stature is located on chromosome 20. Analysis of 10 short tandem repeat polymorphisms localized this linkage to a 3.2cM region that includes D20S98 and D20S66. Using all possible sib-pair combinations, linkage was detected to both stature (P = 0.0001) and to leg length (P = 0.001), but not to sitting height. Single-strand conformational polymorphism analysis of exon 3 of the bone morphogenetic protein 2 (BMP2) gene, a candidate gene in this region, in genomic DNA of 20 of the tallest and 20 of the shortest individuals did not show any consistent differences associated with leg length or height. Sequence analysis of the region encoding the mature protein revealed a single nucleotide substitution, a T to G transversion, not detected by single-strand conformational polymorphism (SSCP) analysis. This transversion results in a conservative amino acid substitution of glycine for valine at codon 80 of BMP2. The frequency of this allele was 0.23 in the sample. No significant differences in height were noted in persons carrying either allele. This indicates that this structural alteration in the mature BMP2 protein does not contribute to the differences in stature observed in the Pima Indians, nor is this structural change in the mature protein likely to be responsible for the linkage observed with stature on chromosome 20. © 1995 Wiley-Liss, Inc.

1 This article is a U.S. Government work and, as such, is in the public domain in the United States of America.

     

Crosstalk between neuropeptides SP and CGRP in regulation of BMP2-induced bone differentiation

ABSTRACT

Aim of the study: The peripheral nervous system is involved in regulation of bone metabolism via sensory and sympathetic innervation. Substance P (SP) and calcitonin gene-related peptide (CGRP) are two sensory neuropeptides that have been associated with regulation of osteogenic differentiation. However, the interaction between SP and CGRP both with each other and the bone morphogenetic protein 2 (BMP2) in regulation of osteogenic differentiation has not been studied. Therefore, the aim of this study was to investigate the interaction between SP and CGRP on BMP2-induced bone differentiation using model progenitor cells. Materials and methods: C2C12 myoblasts and MC3T3 pre-osteoblasts were treated with SP and CGRP, both individually and in combination, in the presence of BMP2. The effects of the neuropeptides on BMP2-induced osteogenic differentiation were assessed by measuring alkaline phosphatase (ALP) activity, mineralization, and expression of osteogenic markers. Results: Both SP and CGRP enhanced BMP2 signaling, Runx2 mRNA expression, as well as mineralization in vitro. Co-stimulation with SP and CGRP resulted in down-regulation of BMP2-induced bone differentiation, suggesting potential crosstalk between the two neuropeptides in regulation of BMP2 signaling. Conclusions: Based on the results shown here, CGRP can mitigate augmenting effects of SP on BMP2 signaling and the three pathways potentially converge on Runx2 to regulate BMP2-induced bone differentiation.