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Osteoprotegerin deficiency results in disruption of posterofrontal suture closure in mice: implications in nonsyndromic craniosynostosis. Plast Reconstr Surg 2015; 135:990e-999e. [PMID: 26017615 DOI: 10.1097/prs.0000000000001284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Little is known about the role of osteoclasts in cranial suture fusion. Osteoclasts are predominantly regulated by receptor activator of nuclear factor kappa B and receptor activator of nuclear factor kappa B ligand, both of which lead to osteoclast differentiation, activation, and survival; and osteoprotegerin, a soluble inhibitor of receptor activator of nuclear factor kappa B. The authors' work examines the role of osteoprotegerin in this process using knockout technology. METHODS Wild-type, osteoprotegerin-heterozygous, and osteoprotegerin-knockout mice were imaged by serial micro-computed tomography at 3, 5, 7, 9, and 16 weeks. Suture density measurements and craniometric analysis were performed at these same time points. Posterofrontal sutures were harvested from mice after the week-16 time point and analyzed by means of histochemistry. RESULTS Micro-computed tomographic analysis of the posterofrontal suture revealed reduced suture fusion in osteoprotegerin-knockout mice compared with wild-type and heterozygous littermates. Osteoprotegerin deficiency resulted in a statistically significant decrease in suture bone density in knockout mice. There was no reduction in the density of non-suture-containing calvarial bone between wild-type and osteoprotegerin-knockout mice. Histochemistry of suture sections supported these micro-computed tomographic findings. Finally, osteoprotegerin-knockout mice had reduced anteroposterior skull distance at all time points and an increased interorbital distance at the week-16 time point. CONCLUSION The authors' data suggest that perturbations in the expression of osteoprotegerin and subsequent changes in osteoclastogenesis lead to alterations in murine cranial and posterofrontal suture morphology.
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2
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Park SS, Beyer RP, Smyth MD, Clarke CM, Timms AE, Bammler TK, Stamper BD, Mecham BH, Gustafson JA, Cunningham ML. Osteoblast differentiation profiles define sex specific gene expression patterns in craniosynostosis. Bone 2015; 76:169-76. [PMID: 25753363 PMCID: PMC4546839 DOI: 10.1016/j.bone.2015.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/18/2015] [Accepted: 03/01/2015] [Indexed: 01/25/2023]
Abstract
Single suture craniosynostosis (SSC) is the premature fusion of one calvarial suture and occurs in 1-1700-2500 live births. Congenital fusion of either the sagittal, metopic, or coronal sutures represents 95% of all cases of SSC. Sagittal and metopic synostosis have a male preponderance (3:1) while premature fusion of the coronal suture has a female preponderance (2:1). Although environmental and genetic factors contribute to SSC, the etiology of the majority of SSC cases remains unclear. In this study, 227 primary calvarial osteoblast cell lines from patients with coronal, metopic, or sagittal synostosis and unaffected controls were established and assayed for ALP activity and BrdU incorporation (n = 226) as respective measures of early stage osteoblast differentiation and proliferation. Primary osteoblast cell lines from individuals with sagittal synostosis demonstrated higher levels of ALP activity and reduced proliferation when compared to control lines. In order to address the sex differences in SSC types, the data was further stratified by sex. Osteoblasts from males and females with sagittal synostosis as well as males with metopic synostosis demonstrated higher levels of ALP activity when compared to sex matched controls, and males with sagittal or metopic synostosis demonstrated reduced levels of proliferation. In order to elucidate genes and pathways involved in these observed phenotypes, correlation analyses comparing ALP activity and proliferation to global gene expression was performed. Transcripts related to osteoblast differentiation were identified both differentially up and downregulated, correlated with ALP activity when compared to controls, and demonstrated a striking sex specific gene expression pattern. These data support that the dysregulation of osteoblast differentiation plays a role in the development of SSC and that genetic factors contribute to the observed sex related differences.
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Affiliation(s)
- Sarah S Park
- Seattle Children's Research Institute, Center for Developmental Biology and Regenerative Medicine, Seattle, WA, USA
| | - Richard P Beyer
- University of Washington, Center for Ecogenetics and Environmental Health, Seattle, WA, USA
| | - Matthew D Smyth
- Washington University, Department of Neurosurgery and St. Louis Children's Hospital, St. Louis, MO, USA
| | - Christine M Clarke
- Seattle Children's Research Institute, Center for Developmental Biology and Regenerative Medicine, Seattle, WA, USA
| | - Andrew E Timms
- Seattle Children's Research Institute, Center for Developmental Biology and Regenerative Medicine, Seattle, WA, USA
| | - Theo K Bammler
- University of Washington, Center for Ecogenetics and Environmental Health, Seattle, WA, USA
| | | | | | - Jennifer A Gustafson
- Seattle Children's Research Institute, Center for Developmental Biology and Regenerative Medicine, Seattle, WA, USA
| | - Michael L Cunningham
- Seattle Children's Research Institute, Center for Developmental Biology and Regenerative Medicine, Seattle, WA, USA; Seattle Children's Craniofacial Center, Seattle, WA, USA.
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3
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Selective serotonin reuptake inhibitor exposure alters osteoblast gene expression and craniofacial development in mice. ACTA ACUST UNITED AC 2014; 100:912-23. [DOI: 10.1002/bdra.23323] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Chim H, Manjila S, Cohen AR, Gosain AK. Molecular signaling in pathogenesis of craniosynostosis: the role of fibroblast growth factor and transforming growth factor–β. Neurosurg Focus 2011; 31:E7. [DOI: 10.3171/2011.5.focus1197] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The interplay of signals between dura mater, suture mesenchyme, and brain is essential in determining the fate of cranial sutures and the pathogenesis of premature suture fusion leading to craniosynostosis. At the forefront of research into suture fusion is the role of fibroblast growth factor and transforming growth factor–β, which have been found to be critical in the cell-signaling cascade involved in aberrant suture fusion. In this review, the authors discuss recent and ongoing research into the role of fibroblast growth factor and transforming growth factor–β in the etiopathogenesis of craniosynostosis.
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Affiliation(s)
- Harvey Chim
- 1Department of Plastic Surgery, Case Western Reserve University; and
| | - Sunil Manjila
- 2Division of Pediatric Neurosurgery, Rainbow Babies and Children's Hospitals, Case Western Reserve University, Cleveland, Ohio
| | - Alan R. Cohen
- 2Division of Pediatric Neurosurgery, Rainbow Babies and Children's Hospitals, Case Western Reserve University, Cleveland, Ohio
| | - Arun K. Gosain
- 1Department of Plastic Surgery, Case Western Reserve University; and
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Cooper TK, Zhong Q, Krawczyk M, Tae HJ, Müller GA, Schubert R, Myers LA, Dietz HC, Talan MI, Briest W. The haploinsufficient Col3a1 mouse as a model for vascular Ehlers-Danlos syndrome. Vet Pathol 2010; 47:1028-39. [PMID: 20587693 PMCID: PMC2970629 DOI: 10.1177/0300985810374842] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Vascular Ehlers-Danlos syndrome is a rare genetic disorder resulting from mutations in the α-1 chain of type III collagen (COL3A1) and manifesting as tissue fragility with spontaneous rupture of the bowel, gravid uterus, or large or medium arteries. The heterozygous Col3a1 knockout mouse was investigated as a model for this disease. The collagen content in the abdominal aorta of heterozygotes was reduced, and functional testing revealed diminishing wall strength of the aorta in these mice. Colons were grossly and histologically normal, but reduced strength and increased compliance of the wall were found in heterozygotes via pressure testing. Although mice demonstrated no life-threatening clinical signs or gross lesions of vascular subtype Ehlers-Danlos syndrome type IV, thorough histological examination of the aorta of heterozygous mice revealed the presence of a spectrum of lesions similar to those observed in human patients. Lesions increased in number and severity with age (0/5 [0%] in 2-month-old males vs 9/9 [100%] in 14-month-old males, P < .05) and were more common in male than female mice (23/26 [88.5%] vs 14/30 [46.7%] in 9- to 21-month-old animals, P < .05). Haploinsufficiency for Col3a1 in mice recapitulates features of vascular Ehlers-Danlos syndrome in humans and can be used as an experimental model.
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Affiliation(s)
- T K Cooper
- Penn State Hershey Medical Center, Department of Comparative Medicine, H054, 500 University Dr., Hershey, PA 17033-0850, USA.
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6
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Abstract
BACKGROUND Craniosynostosis, the premature fusion of cranial sutures, results in serious neurologic and morphologic abnormalities when left untreated. Surgical excision of the fused sutures and remodeling of the skull remains the standard therapy. Development of novel, minimally invasive therapies for craniosynostosis will undoubtedly be dependent on a more thorough understanding of the molecular mechanisms underlying this abnormality. Significant evidence suggests the influence of regional dura mater on the behavior of the overlying suture complex. The mouse model has been instrumental in investigating this observation because of the natural juxtaposition of the posterior frontal suture, which fuses early in life, with the other cranial sutures, which remain patent. METHODS The authors used microarray analysis to compare genomic changes in the dura mater underlying the posterior frontal and sagittal sutures of mice. Suture-associated dura mater was harvested from mice before (postnatal day 5), during (postnatal day 10), and after (postnatal day 20) posterior frontal suture fusion (n = 20 mice for each of the three time points). RESULTS Microarray results confirmed differential regulation of genes involved in paracrine signaling, extracellular matrix, and bone remodeling between the dura mater underlying the fusing posterior frontal suture and the patent sagittal suture. CONCLUSIONS These data confirm global differences in gene expression between regional dura mater underlying fusing and patent sutures. These results provide further insight into potential molecular mechanisms that may play a role in cranial suture biology.
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Global age-dependent differences in gene expression in response to calvarial injury. J Craniofac Surg 2009; 19:1292-301. [PMID: 18812854 DOI: 10.1097/scs.0b013e3181843609] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Children less than 2 years of age are capable of healing large calvarial defects, whereas adults have been found to lack this endogenous ability. In this study, we used microarray analysis to compare genomewide expression patterns during active regeneration after injury with calvaria in skeletally immature and mature mice. Parietal bone defects were created in 6-day-old (juvenile) and 60-day-old (adult) mice using a 4-mm trephine bit (n = 20 mice per age group). The calvarial disc was removed, leaving the underlying dura mater intact. Two weeks after injury, the region of regeneration with the underlying dura mater was harvested, and RNA was extracted for microarray analysis. The 25 most differentially upregulated genes in juvenile regenerates compared with adults were listed, as well as selected bone-related genes. In addition, QRT-PCR confirmation of specific genes was performed for validation. Juvenile regenerates expressed significantly greater amounts of BMP-2, -4, -7, as well as FGF-2 and its receptor FGFR-1. Various other growth factors were also noted to be upregulated, including IGF-2 and Ptn. This corresponded with the increased expression of markers for osteogenic differentiation of Sparc and Oc. Markers of osteoclast activity, Acp5, Ctsk, and Mmp2, were noted to be greater in juvenile regenerates compared with adults. The observation of Mmp14 upregulation, however, highlights the importance of balanced osteoclast-mediated bone resorption for ultimate healing. The 2 most differentially regulated genes, transthyretin (Ttr) and prostaglandin D2 synthase (Ptgds), highlight the potential role of retinoic acid signaling and the prostaglandin axis on skeletal regeneration. These findings underscore the multitude of biomolecular mechanisms at play, allowing juvenile calvaria to heal after injury. The identification of various growth factors and cytokines involved also suggests novel therapeutic strategies for tissue-engineering purposes.
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8
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Definition of topographic organization of skull profile in normal population and its implications on the role of sutures in skull morphology. J Craniofac Surg 2008; 19:27-36. [PMID: 18216661 DOI: 10.1097/scs.0b013e31815ca07a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The geometric configuration of the skull is complex and unique to each individual. This study provides a new technique to define the outline of skull profile and attempt to find the common factors defining the ultimate skull configuration in adult population. Ninety-three lateral skull x-ray from the computed tomographic scan films were selected and digitized. The lateral skull surface was divided into 3 regions based on the presumed location of the coronal and lambdoid sutures. Three main curvatures (frontal, parietal, occipital) were consistently identified to overlap the skull periphery. The radius, cord length, and inclination of each curvature were measured. The average values for 3 defined curvatures of the skull profile were recorded. Factor analysis of the measured values produced 3 factors explaining the skull profile. The first factor explained 32% of total variance and was related to the overall size of the head as represented by total length and the radius of the curvature in the vertex and back of the head. The second factor covered 26% of the variance representing the inverse correlation between the angle of the frontal and parietal curves. The third factor revealed the direct correlation of the occipital and parietal angle. In all of these factors, the frontal zone variation was independent or opposite of the parieto-occipital zone. A strong association between the total length of the skull, occipital curve radius, and length with the sex was shown. In conclusion, the skull profile topography has large variation and can be defined mathematically by 2 distinct territories: frontal and parieto-occipital zones. These territories hinge on the coronal suture. Therefore, the coronal suture may play a dominant role in final skull configuration.
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Wan DC, Pomerantz JH, Brunet LJ, Kim JB, Chou YF, Wu BM, Harland R, Blau HM, Longaker MT. Noggin suppression enhances in vitro osteogenesis and accelerates in vivo bone formation. J Biol Chem 2007; 282:26450-9. [PMID: 17609215 DOI: 10.1074/jbc.m703282200] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several investigations have demonstrated a precise balance to exist between bone morphogenetic protein (BMP) agonists and antagonists, dictating BMP signaling and osteogenesis. We report a novel approach to manipulate BMP activity through a down-regulation of the potent BMP antagonist Noggin, and examined the effects on the bone forming capacity of osteoblasts. Reduction of noggin enhanced BMP signaling and in vitro osteoblast bone formation, as demonstrated by both gene expression profiles and histological staining. The effects of noggin suppression on in vivo bone formation were also investigated using critical-sized calvarial defects in mice repaired with noggin-suppressed osteoblasts. Radiographic and histological analyses revealed significantly more bone regeneration at 2 and 4 weeks post-injury. These findings strongly support the concept of enhanced osteogenesis through a down-regulation in Noggin and suggest a novel approach to clinically accelerate bone formation, potentially allowing for earlier mobilization of patients following skeletal injury or surgical resection.
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Affiliation(s)
- Derrick C Wan
- Department of Surgery, Stanford University School of Medicine, Stanford University, Stanford, California 94305, USA
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10
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Wan DC, Siedhoff MT, Kwan MD, Nacamuli RP, Wu BM, Longaker MT. Refining Retinoic Acid Stimulation for Osteogenic Differentiation of Murine Adipose-Derived Adult Stromal Cells. ACTA ACUST UNITED AC 2007; 13:1623-31. [PMID: 17518707 DOI: 10.1089/ten.2006.0283] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Murine adipose-derived adult stromal cells (ADAS) seeded onto appropriate scaffolds and pre-incubated with retinoic acid have been shown to generate in vivo bone rapidly. Prompt resorption ensues, however, as a result of osteoclastogenesis, likely secondary to retinoic acid carryover. In this study, we determined the effects of abbreviated retinoic acid exposure on ADAS osteogenic differentiation. Histological staining and gene expression analysis revealed that longer retinoic acid exposure resulted in better in vitro bone differentiation. However, significant osteogenesis was observed in ADAS after just 15 days of retinoic acid supplementation, suggesting that continual culture with retinoic acid is unnecessary for initiation of the osteogenic program. This was confirmed using ADAS pre-incubated in monolayer with an abbreviated 15 days of retinoic acid exposure before implantation into critical-sized calvarial defects. Similar rates of regeneration were observed between ADAS exposed to for 15 days or for a full 25-day course of retinoic acid before defect repair. Furthermore, by limiting retinoic acid exposure to ADAS in monolayer without scaffold, accelerated bone formation was observed without concomitant osteoclastic resorption. These data suggest that skeletal regeneration may be improved by modulating retinoic acid exposure before implantation, markedly accelerating the repair of bone defects using ADAS.
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Affiliation(s)
- Derrick C Wan
- Department of Surgery, School of Medicine, Stanford University, Stanford, California 94305-5148, USA
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11
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Wan DC, Aalami OO, Wang Z, Nacamuli RP, Lorget F, Derynck R, Longaker MT. Differential gene expression between juvenile and adult dura mater: a window into what genes play a role in the regeneration of membranous bone. Plast Reconstr Surg 2006; 118:851-861. [PMID: 16980845 DOI: 10.1097/01.prs.0000232366.23897.2b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although reossification of large calvarial defects is possible in children, adults lack this tissue engineering capacity. In this study, the authors compared the differences in gene expression between juvenile and adult dura mater using a mouse cDNA microarray with 42,000 unique elements. METHODS Non-suture-associated parietal bone was harvested from 6-day-old and 60-day-old mice. The dura mater was carefully dissected from the calvarial disk and snap-frozen. RNA was extracted from pooled dura mater for microarray analysis. The 25 most differentially expressed genes were listed, as were selected bone-related genes. In addition, quantitative real-time reverse-transcriptase polymerase chain reaction confirmation of selected genes-BMP-2, BMP-4, and BMP-7; and osteopontin (OP), osteocalcin (OC), and FGFR-1-was performed. RESULTS Juvenile dura mater expressed significantly greater amounts of BMP-2 and OP. Minimal difference in OC expression was observed between juvenile and adult dura mater. Extracellular matrix proteins (Col3a1, 5a1, 6a1, and fibronectin 1), osteoblast differentiation markers (Runx2/Cbfa1, Itm2a, and FGFR-1), and the growth factor Ptn were among other genes with greater expression in juvenile dura mater. Markers of osteoclasts (Acp5, MMP9, Ctsk) and the multiple candidate gene Ntrk2 were also expressed at higher levels in the juvenile dura mater. CONCLUSIONS These findings suggest a more differentiated osteoprogenitor population to exist along with a greater presence of osteoclasts in the juvenile dura mater relative to adults. In addition to establishing a baseline difference in gene expression between juvenile and adult dura mater, new genes potentially critical to the regenerative potential of juvenile calvaria were identified.
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Affiliation(s)
- Derrick C Wan
- Stanford and San Francisco, Calif. From the Department of Surgery, Stanford University School of Medicine, Stanford University, and the Departments of Surgery and Cell and Tissue Biology, University of California, San Francisco
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12
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Singh R, Recinos RF, Agresti M, Schaefer RB, Bosbous M, Gosain AK. Real-time reverse transcriptase polymerase chain reaction: an improvement in detecting mRNA levels in mouse cranial tissue. Plast Reconstr Surg 2006; 117:2227-34. [PMID: 16772922 DOI: 10.1097/01.prs.0000219339.82624.b9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Quantitation of messenger RNA levels has traditionally been carried out by Northern blot analysis. While this is regarded as the standard method, it is time-consuming and requires large quantities of RNA. Reverse-transcriptase polymerase chain reaction is a semiquantitative method that has been used as a more rapid and sensitive alternative to Northern blotting. Real-time reverse-transcriptase polymerase chain reaction is a quantitative technique that is gaining widespread acceptance as a rapid and reliable way of quantifying mRNA. Since both techniques are currently being used to evaluate gene expression in the murine cranial suture model, the present study was performed to compare the sensitivity and variability of real-time to conventional reverse-transcriptase polymerase chain reaction in this model. METHODS Mouse brain RNA was isolated and amplified using real-time and conventional methods. For the real-time method, a serial 10-fold dilution of RNA, ranging from 1 fg to 100 ng, was performed. For the conventional method, the minimum amount of RNA needed for consistent polymerase chain reaction amplification was determined. Transforming growth factor beta-1 and beta-actin RNA transcripts were measured using both techniques. RESULTS One femtogram of RNA could be detected by the real-time method, although 10 fg were required to reliably detect differences; 500 ng of RNA was required for consistent polymerase chain reaction amplification using the conventional method. The variability of real-time reverse-transcriptase polymerase chain reaction when expressed as a coefficient of variation (SD as a percentage of the mean) ranged from 0.23 to 2.6 percent for all genes tested, as compared with 9 to 70 percent for conventional reverse-transcriptase polymerase chain reaction. CONCLUSIONS Real-time reverse-transcriptase polymerase chain reaction was used successfully to detect mRNA from different mouse genes. The real-time method is much more sensitive in detecting small amounts of mRNA than both Northern blot analysis and conventional polymerase chain reaction. The variability of the real-time method is more than 10-fold lower compared with the conventional method performed in the authors' laboratory for all genes tested.
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Affiliation(s)
- Rashmi Singh
- Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, Wis. 53226, USA
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13
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Jacob AL, Smith C, Partanen J, Ornitz DM. Fibroblast growth factor receptor 1 signaling in the osteo-chondrogenic cell lineage regulates sequential steps of osteoblast maturation. Dev Biol 2006; 296:315-28. [PMID: 16815385 PMCID: PMC2077084 DOI: 10.1016/j.ydbio.2006.05.031] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 05/02/2006] [Accepted: 05/23/2006] [Indexed: 12/29/2022]
Abstract
Mutations in fibroblast growth factor receptors (Fgfrs) 1-3 cause skeletal disease syndromes in humans. Although these Fgfrs are expressed at various stages of chondrocyte and osteoblast development, their function in specific skeletal cell types is poorly understood. Using conditional inactivation of Fgfr1 in osteo-chondrocyte progenitor cells and in differentiated osteoblasts, we provide evidence that FGFR1 signaling is important for different stages of osteoblast maturation. Examination of osteogenic markers showed that inactivation of FGFR1 in osteo-chondro-progenitor cells delayed osteoblast differentiation, but that inactivation of FGFR1 in differentiated osteoblasts accelerated differentiation. In vitro osteoblast cultures recapitulated the in vivo effect of FGFR1 on stage-specific osteoblast maturation. In immature osteoblasts, FGFR1 deficiency increased proliferation and delayed differentiation and matrix mineralization, whereas in differentiated osteoblasts, FGFR1 deficiency enhanced mineralization. Furthermore, FGFR1 deficiency in differentiated osteoblasts resulted in increased expression of Fgfr3, a molecule that regulates the activity of differentiated osteoblasts. Mice lacking Fgfr1, either in progenitor cells or in differentiated osteoblasts, showed increased bone mass as adults. These data demonstrate that signaling through FGFR1 in osteoblasts is necessary to maintain the balance between bone formation and remodeling through a direct effect on osteoblast maturation.
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MESH Headings
- Animals
- Bone and Bones/abnormalities
- Bone and Bones/embryology
- Bone and Bones/enzymology
- Cell Differentiation/genetics
- Cell Differentiation/physiology
- Cell Lineage/genetics
- Cell Lineage/physiology
- Cells, Cultured
- Chondrocytes/cytology
- Chondrocytes/enzymology
- Chondrocytes/physiology
- Hypertrophy/genetics
- Mice
- Mice, Knockout
- Mice, Transgenic
- Osteoblasts/cytology
- Osteoblasts/enzymology
- Osteoblasts/physiology
- Receptor, Fibroblast Growth Factor, Type 1/biosynthesis
- Receptor, Fibroblast Growth Factor, Type 1/deficiency
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Signal Transduction/genetics
- Signal Transduction/physiology
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Affiliation(s)
- Anne L. Jacob
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Craig Smith
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Juha Partanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - David M. Ornitz
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
- * Corresponding author. E-mail address: (D.M. Ornitz)
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14
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Farhadi J, Jaquiery C, Barbero A, Jakob M, Schaeren S, Pierer G, Heberer M, Martin I. Differentiation-dependent up-regulation of BMP-2, TGF-beta1, and VEGF expression by FGF-2 in human bone marrow stromal cells. Plast Reconstr Surg 2006; 116:1379-86. [PMID: 16217482 DOI: 10.1097/01.prs.0000182355.67397.5a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Bone tissue formation by bone marrow stromal cells may be supported and enhanced by multiple growth factors, particularly in cases of a compromised local microenvironment. In this study, the authors hypothesized that fibroblast growth factor (FGF)-2 can stimulate the production by human bone marrow stromal cells of osteogenic [i.e., bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1] and angiogenic [i.e., vascular endothelial growth factor (VEGF)] factors. METHODS Human bone marrow stromal cells from six donors were expanded for two passages (expansion phase) and subsequently cultivated in osteogenic medium containing ascorbic acid, beta-glycerophosphate, and dexamethasone (differentiation phase). After each phase, cells were transferred into serum-free medium with or without FGF-2 at different concentrations and for different times, and the expression of BMP-2, TGF-beta1, and VEGF was quantified at the mRNA level by real-time quantitative reverse-transcriptase polymerase chain reaction. The amounts of TGF-beta1 and VEGF released in the culture medium were assessed using enzyme-linked immunosorbent assay kits and normalized to the DNA content. RESULTS In response to 5 ng/ml FGF-2 for 24 hours, the mRNA expression of VEGF increased at both culture phases (up to 6.1 fold), whereas that of BMP-2 and TGF-beta1 significantly increased only after the expansion (3.1-fold) or differentiation phase (2.1-fold), respectively. Similar trends were observed in the amounts of proteins measured in the culture medium. CONCLUSIONS The authors' results indicate that FGF-2 up-regulates the expression of BMP-2, TGF-beta1, and VEGF in human bone marrow stromal cells, in a pattern dependent on the cell-differentiation stage. These findings prompt for in vivo investigations on the delivery of FGF-2 for the temporally/functionally regulated enhancement of bone marrow stromal cell-based bone induction.
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Affiliation(s)
- Jian Farhadi
- Department of Surgery, University Hospital Basel, Basel, Switzerland
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15
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Aalami OO, Nacamuli RP, Salim A, Fong KD, Lenton KA, Song HM, Fang TD, Longaker MT. Differential transcriptional expression profiles of juvenile and adult calvarial bone. Plast Reconstr Surg 2006; 115:1986-94. [PMID: 15923847 DOI: 10.1097/01.prs.0000163323.66318.73] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND It has widely been observed that young children are capable of reossifying large calvarial defects, while adults lack this endogenous tissue-engineering capacity. The ability of juvenile animals to regenerate calvarial defects has been investigated in multiple animal models, including mice. In this study, the authors used cDNA microarrays to investigate the expression of osteogenesis-associated genes upstream and downstream of Runx2 in juvenile and adult mouse calvaria. METHODS Nonsuture-associated parietal bone discs were harvested from 6-day-old (n = 50) and 60-day-old (n = 35) male CD-1 mice. After separation of the underlying dura mater and overlying pericranium, the calvarial discs were snap-frozen and RNA was extracted from pooled samples of calvaria for microarray analysis. Genes analyzed included cytokines, receptors, and cell-surface and matrix proteins both upstream and downstream of Runx2. RESULTS Genes associated with the Runx2 pathway had notably higher levels in the juvenile versus adult calvaria. All genes except for osteocalcin were expressed at least twofold higher in the juvenile calvaria. This pattern was validated with quantitative real-time polymerase chain reaction. In addition, mRNA for potent osteoinductive growth factors was present at higher levels in the juvenile compared with the adult calvaria. CONCLUSIONS These findings reflect a genomic environment of active osteoblast differentiation and ossification in the juvenile calvaria compared with the adult "quiescent" calvarial tissue. These data suggest that a decreased osteogenic potential of adult calvarial osteoblasts may, in part, explain the inability of adult animals to heal calvarial defects.
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Affiliation(s)
- Oliver O Aalami
- Department of Surgery, Stanford University School of Medicine, Stanford, Calif 94305-5148, USA
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16
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Nacamuli RP, Fong KD, Lenton KA, Song HM, Fang TD, Salim A, Longaker MT. Expression and Possible Mechanisms of Regulation of BMP3 in Rat Cranial Sutures. Plast Reconstr Surg 2005; 116:1353-62. [PMID: 16217479 DOI: 10.1097/01.prs.0000182223.85978.34] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Clinical genetics data and investigative studies have contributed greatly to our understanding of the role of numerous genes in craniosynostosis. Recent studies have introduced antagonists of osteogenesis as potential key regulators of suture fusion and patency. The authors investigated the expression pattern of the bone morphogenetic protein antagonist BMP3 in rat cranial sutures and the factors regulating its expression in vitro. METHODS Microarray analysis was performed on rat posterior frontal and sagittal cranial sutures at 5, 10, 15, 20, and 30 days of life (n = 30 per group). Gene expression was confirmed using quantitative real-time reverse transcriptase polymerase chain reaction. Regulation of BMP3 expression was determined using primary rat calvarial osteoblasts stimulated with recombinant human fibroblast growth factor 2 or recombinant human transforming growth factor beta1, or cultured with primary rat nonsuture dura mater. Gene expression was quantified with quantitative real-time reverse transcriptase polymerase chain reaction. RESULTS BMP3 expression in the posterior frontal suture decreased over the time course analyzed, whereas it increased in the sagittal suture. Notably, BMP3 expression was higher in the patent sagittal suture during the window of posterior frontal suture fusion. Stimulation of osteoblasts with recombinant human fibroblast growth factor 2 led to a rapid and sustained suppression of BMP3 expression (85 percent, p < 0.01) when compared with controls. Co-culture with dural cells decreased BMP3 mRNA by 50 percent compared with controls (p < 0.01). CONCLUSIONS BMP3 is expressed in rat cranial sutures in a temporal pattern suggesting involvement in cranial suture patency and fusion. Furthermore, BMP3 is regulated in calvarial osteoblasts by recombinant human fibroblast growth factor 2 and by paracrine signaling from dura mater. These data add to our knowledge of the role of osteogenic antagonists in cranial suture biology.
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Affiliation(s)
- Randall P Nacamuli
- Department of Surgery, Stanford University School of Medicine, Stanford, California 94305-5148, USA
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17
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Nacamuli RP, Song HM, Fang TD, Fong KD, Mathy JA, Shi YY, Salim A, Longaker MT. Quantitative transcriptional analysis of fusing and nonfusing cranial suture complexes in mice. Plast Reconstr Surg 2005; 114:1818-25. [PMID: 15577353 DOI: 10.1097/01.prs.0000143578.41666.2c] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previous studies have documented the differences in expression of various genes associated with the process of osteogenesis in fusing and nonfusing cranial sutures, including growth factors, growth factor receptors, and extracellular matrix molecules. Most of these studies were performed in rats, and although the biology regulating cranial suture fusion in mice and rats is presumed to be similar, studies are needed to verify these expression patterns as mice become increasingly utilized for scientific inquiry into the molecular biology of suture fusion and patency. The purpose of this study was to determine the differences in expression of several genes known to be critical to osteoblast biology. Posterior frontal and sagittal suture complexes (including the associated dura mater, suture mesenchyme, and osteogenic fronts) were isolated from 5-, 15-, 25-, 35-, and 45-day-old male CD-1 mice (n = 8 per age; n = 40 total). Total cellular RNA was extracted and converted to cDNA. Quantitative real-time reverse transcriptase polymerase chain reaction was then performed for the following genes: transforming growth factor beta1 and beta3, fibroblast growth factor receptor 1, Runx2,Osteopontin, and Osteocalcin. Expression of all genes examined was increased significantly in the posterior frontal suture as compared with the sagittal suture. Peak expression for all genes was observed on day 25. These data demonstrate that the expression of osteogenic growth factors, growth factor receptors, transcription factors, and extracellular matrix molecules is increased in the fusing posterior frontal suture in mice.
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Affiliation(s)
- Randall P Nacamuli
- Department of Surgery, Stanford University School of Medicine, Stanford, Calif 94305-5148, USA
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18
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Abstract
The birth prevalence of craniosynostosis (premature suture fusion) is 300-500 per 1,000,000 live births. Surgical management involves the release of the synostosed suture. In many cases, however, the suturectomy site rapidly reossifies, further restricts the growing brain and alters craniofacial growth. This resynostosis requires additional surgery, which increases patient morbidity and mortality. New findings in bone biology and molecular pathways involved with suture fusion, combined with novel tissue engineering techniques, may allow the design of targeted and complementary therapies to decrease complications inherent in high-risk surgical procedures. This paper selectively reviews recent advances in i) identifying genetic mutations and the aetiopathogenesis of a number of craniosynostotic conditions; ii) cranial suture biology and molecular biochemical pathways involved in suture fusion; and iii) the design, development and application of various vehicles and tissue engineered constructs to deliver cytokines and genes to cranial sutures. Such biologically based therapies may be used as surgical adjuncts to rescue fusing sutures or help manage postoperative resynostosis.
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Affiliation(s)
- Mark P Mooney
- Department of Oral Medicine and Pathology, School of Dental Medicine, 329 Salk Hall, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Spector JA, Mathy JA, Warren SM, Nacamuli RP, Song HM, Lenton K, Fong KD, Fang DT, Longaker MT. FGF-2 Acts through an ERK1/2 Intracellular Pathway to Affect Osteoblast Differentiation. Plast Reconstr Surg 2005; 115:838-52. [PMID: 15731686 DOI: 10.1097/01.prs.0000153035.73507.7b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An abundance of genetic and experimental data have suggested that fibroblast growth factor (FGF) signaling plays a central role in physiological and pathological cranial suture fusion. Although alterations in the differentiation and proliferation of sutural osteoblasts may be a key mediator of this process, the mechanisms by which FGF signaling regulates osteoblast differentiation remain incompletely understood. In the current study, the authors show that recombinant human FGF-2 alters osteoblastic expression of bone morphogenetic protein-2 and Msx-2 in vitro to favor cellular differentiation and osteoinduction. The ERK1/2 intracellular signaling cascade was shown to be necessary for recombinant human FGF-2-mediated bone morphogenetic protein-2 transcriptional changes. Furthermore, the cellular production of an intermediate transcriptional modifier was found to be necessary for the recombinant human FGF-2-mediated gene expression changes in bone morphogenetic protein-2 and Msx-2. Together, these findings offer new insight into the mechanisms by which FGF-2 modulates osteoblast biology.
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Affiliation(s)
- Jason A Spector
- Department of Surgery, Stanford University School of Medicine, Stanford, Calif 94305-5148, USA
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Fang TD, Nacamuli RP, Song HM, Fong KD, Warren SM, Salim A, Carano RAD, Filvaroff EH, Longaker MT. Creation and characterization of a mouse model of mandibular distraction osteogenesis. Bone 2004; 34:1004-12. [PMID: 15193546 DOI: 10.1016/j.bone.2004.02.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 01/29/2004] [Accepted: 02/02/2004] [Indexed: 10/26/2022]
Abstract
While the histological and ultrastructural changes associated with distraction osteogenesis have been extensively characterized using various animal models, the molecular mechanisms governing this technique remain poorly understood. In the current study, for the first time, we describe a mouse mandibular distraction osteogenesis model. Development of this model will allow assessment of factors involved in normal vs. abnormal healing (especially in non-unions) of craniofacial skeletal elements. Complete osteotomies were created on the right hemimandibles of 51 adult male CD-1 mice and customized distraction devices attached. Thirty-three animals underwent gradual distraction (5 days latency, distraction at 0.2 mm BID x 8 days, 28 days consolidation), while the remaining 18 mice underwent acute lengthening (immediate distraction to 3.2 mm) at the time of surgery. Mandibles were harvested at time points corresponding to the latent (POD 5), distraction (POD 9, 13), and consolidation (POD 28, 41) periods and processed for histological or quantitative real-time RT-PCR analysis. Specimens from each group were processed for microCT analysis. Histological and radiological data demonstrated that all mandibles undergoing gradual distraction achieved complete bony union by the end of consolidation, while those undergoing acute lengthening formed a fibrous non-union. Quantitative real-time RT-PCR demonstrated upregulation of mRNA for VEGF, FGF-2, collagen I, and osteopontin during gradual distraction but not during acute lengthening. These data validate our novel mouse mandibular distraction model and demonstrate its utility in elucidating the molecular mechanisms regulating bone formation during distraction osteogenesis as compared to those that are expressed during the formation of fibrous non-unions.
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Affiliation(s)
- Tony D Fang
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
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Song HM, Sahar DE, Fong KD, Nacamuli RP, Fang TD, Mathy JA, Aalami OO, Warren SM, Longaker MT. In Vitro Murine Posterior Frontal Suture Fate Is Age-Dependent:. Plast Reconstr Surg 2004; 113:1192-204. [PMID: 15083020 DOI: 10.1097/01.prs.0000110203.90911.63] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In CD-1 mice, the posterior frontal suture (analogous to the human metopic suture) fuses while all other cranial sutures remain patent. In an in vitro organ culture model, the authors previously demonstrated that posterior frontal sutures explanted immediately before the onset of suture fusion (at 25 days old) mimic in vivo physiologic fusion. In the first portion of this study, the authors defined how early in development the posterior frontal suture fuses in their tension-free, serum-free organ culture system by serially analyzing posterior frontal suture fusion from calvariae explanted at different stages of postnatal development. Their results revealed a divergence of suture fate leading to abnormal patency or physiologic fusion between the first and second weeks of life, respectively, despite viability and continued growth of the calvarial explants in vitro. From these data, the authors postulated that the gene expression patterns present in the suture complex at the time of explant may determine whether the posterior frontal suture fuses or remains patent in organ culture. Therefore, to elucidate potentially important differences in gene expression within this "window of opportunity," they performed a cDNA microarray analysis on 5-day-old and 15-day-old posterior frontal and sagittal whole suture complexes corresponding to the age ranges for unsuccessful (1 to 7 days old) and successful (14 to 21 days old) in vitro posterior frontal suture fusion. Overall, their microarray results reveal interesting differential expression patterns of candidate genes in different categories, including angiogenic cytokines and mechanosensitive genes potentially important in cranial suture biology.
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Affiliation(s)
- HanJoon M Song
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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Song HM, Nacamuli RP, Xia W, Bari AS, Shi YY, Fang TD, Longaker MT. High-dose retinoic acid modulates rat calvarial osteoblast biology. J Cell Physiol 2004; 202:255-62. [PMID: 15389522 DOI: 10.1002/jcp.20115] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Retinoic acid has been shown to adversely affect craniofacial development. Cleft palate and craniosynostosis are two examples of craniofacial defects associated with prenatal exposure to this agent. Although the effects of retinoic acid on cephalic neural crest-derived tissues have previously been studied, the specific effects of retinoic acid on the cellular biology of osteoblasts remain unclear. The purpose of this study was to analyze in detail the effects of pharmacologic doses of retinoic acid on the differentiation and proliferation of osteoblasts derived from an intramembranous source. Primary rat calvarial osteoblasts were established in culture and treated with 1 or 10 microM all-trans-retinoic acid. Retinoic acid treatment markedly increased expression of osteopontin up to 48 h after stimulation. Consistent with this early stage of differentiation, both mRNA and protein analysis of FGF receptor isoforms demonstrated a switch in predominance from fibroblast growth factor receptor 2 (fgfr2) to fgfr1. Analysis of PCNA protein confirmed inhibition of proliferation by retinoic acid. To determine whether these alterations in osteoblast biology would lead to increased differentiation, we examined short term [alkaline phosphatase (AP) activity] and long term (von Kossa staining) surrogates of bone formation in vitro. These assays confirmed that retinoic acid increased osteogenesis, with a 4-fold increase in bone nodule formation in cells treated with 10 microM retinoic acid after 28 days. Overall, our results demonstrated that pharmacologic doses of all-trans-retinoic acid decreased osteoblast proliferation and increased differentiation, suggesting that retinoic acid may effect craniofacial development by pathologically enhancing osteogenesis.
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MESH Headings
- Alkaline Phosphatase/drug effects
- Alkaline Phosphatase/physiology
- Animals
- Animals, Newborn
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Proliferation/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Female
- Maxillofacial Abnormalities/chemically induced
- Maxillofacial Abnormalities/metabolism
- Maxillofacial Abnormalities/physiopathology
- Maxillofacial Development/drug effects
- Maxillofacial Development/physiology
- Osteoblasts/drug effects
- Osteoblasts/metabolism
- Osteopontin
- Pregnancy
- Prenatal Exposure Delayed Effects
- Proliferating Cell Nuclear Antigen/drug effects
- Proliferating Cell Nuclear Antigen/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor Protein-Tyrosine Kinases/drug effects
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, Fibroblast Growth Factor, Type 1
- Receptor, Fibroblast Growth Factor, Type 2
- Receptors, Fibroblast Growth Factor/drug effects
- Receptors, Fibroblast Growth Factor/metabolism
- Sialoglycoproteins/drug effects
- Sialoglycoproteins/metabolism
- Skull/cytology
- Skull/drug effects
- Skull/growth & development
- Tretinoin/pharmacology
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
- Hanjoon M Song
- The Department of Surgery, Stanford University School of Medicine, Stanford, California 94305-5148, USA
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