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Transcriptional analysis of cleft palate in TGFβ3 mutant mice. Sci Rep 2020; 10:14940. [PMID: 32913205 PMCID: PMC7483747 DOI: 10.1038/s41598-020-71636-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/17/2020] [Indexed: 12/30/2022] Open
Abstract
Cleft palate (CP) is one of the most common craniofacial birth defects, impacting about 1 in 800 births in the USA. Tgf-β3 plays a critical role in regulating murine palate development, and Tgf-β3 null mutants develop cleft palate with 100% penetrance. In this study, we compared global palatal transcriptomes of wild type (WT) and Tgf-β3 −/− homozygous (HM) mouse embryos at the crucial palatogenesis stages of E14.5, and E16.5, using RNA-seq data. We found 1,809 and 2,127 differentially expressed genes at E16.5 vs. E14.5 in the WT and HM groups, respectively (adjusted p < 0.05; |fold change|> 2.0). We focused on the genes that were uniquely up/downregulated in WT or HM at E16.5 vs. E14.5 to identify genes associated with CP. Systems biology analysis relating to cell behaviors and function of WT and HM specific genes identified functional non-Smad pathways and preference of apoptosis to epithelial-mesenchymal transition. We identified 24 HM specific and 11 WT specific genes that are CP-related and/or involved in Tgf-β3 signaling. We validated the expression of 29 of the 35 genes using qRT-PCR and the trend of mRNA expression is similar to that of RNA-seq data . Our results enrich our understanding of genes associated with CP that are directly or indirectly regulated via TGF-β.
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Zemet R, Amdur-Zilberfarb I, Shapira M, Ziv-Baran T, Hoffmann C, Kassif E, Katorza E. Prenatal diagnosis of congenital head, face, and neck malformations-Is complementary fetal MRI of value? Prenat Diagn 2019; 40:142-150. [PMID: 31664716 DOI: 10.1002/pd.5593] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/30/2019] [Accepted: 10/11/2019] [Indexed: 11/09/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the role of fetal magnetic resonance imaging (MRI) as a complement to ultrasound (US) in the prenatal diagnosis of craniofacial anomalies. METHODS A historical cohort study including all pregnant women who were referred for fetal MRI because of antenatal diagnosis of craniofacial anomalies on screening US. Prenatal diagnostic US, MRI, and postnatal diagnosis were compared for consistencies and discrepancies. RESULTS Forty-five pregnant women with 73 suspected fetal craniofacial anomalies diagnosed by US underwent MRI. In 40 out of 73 anomalies (54.8%), US and MRI findings were in complete agreement with postnatal diagnoses. MRI correctly ruled out the diagnosis of 24 anomalies suspected on US and diagnosed four additional pathologies that were not demonstrated by US. Out of the 85 anomalies (suspected by imaging or confirmed postnatally), confident diagnosis could be made by MRI in 68 anomalies (80%), not diagnosed in 10 (11.8%), and over-diagnosed in seven (8.2%). By US, confident diagnosis could be made in 44 anomalies (51.8%), not diagnosed in 11 (12.9%), and over-diagnosed in 30 (35.3%). CONCLUSION MRI is valuable in the antenatal evaluation of fetal craniofacial anomalies and may be useful as an adjunct to US in the prenatal work-up of craniofacial anomalies.
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Affiliation(s)
- Roni Zemet
- Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Moran Shapira
- Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tomer Ziv-Baran
- School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chen Hoffmann
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Diagnostic Radiology, Sheba Medical Center, Ramat Gan, Israel
| | - Eran Kassif
- Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eldad Katorza
- Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Zhang L, Chen P, Chen L, Weng T, Zhang S, Zhou X, Zhang B, Liu L. Inhibited Wnt signaling causes age-dependent abnormalities in the bone matrix mineralization in the Apert syndrome FGFR2(S252W/+) mice. PLoS One 2015; 10:e112716. [PMID: 25693202 PMCID: PMC4333342 DOI: 10.1371/journal.pone.0112716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/14/2014] [Indexed: 01/16/2023] Open
Abstract
Apert syndrome (AS) is a type of autosomal dominant disease characterized by premature fusion of the cranial sutures, severe syndactyly, and other abnormalities in internal organs. Approximately 70% of AS cases are caused by a single mutation, S252W, in fibroblast growth factor receptor 2 (FGFR2). Two groups have generated FGFR2 knock-in mice Fgfr2S252W/+ that exhibit features of AS. During the present study of AS using the Fgfr2S252W/+ mouse model, an age-related phenotype of bone homeostasis was discovered. The long bone mass was lower in 2 month old mutant mice than in age-matched controls but higher in 5 month old mutant mice. This unusual phenotype suggested that bone marrow-derived mesenchymal stem cells (BMSCs), which are vital to maintain bone homeostasis, might be involved. BMSCs were isolated from Fgfr2S252W/+ mice and found that S252W mutation could impair osteogenic differentiation BMSCs but enhance mineralization of more mature osteoblasts. A microarray analysis revealed that Wnt pathway inhibitors SRFP1/2/4 were up-regulated in mutant BMSCs. This work provides evidence to show that the Wnt/β-catenin pathway is inhibited in both mutant BMSCs and osteoblasts, and differentiation defects of these cells can be ameliorated by Wnt3a treatment. The present study suggested that the bone abnormalities caused by deregulation of Wnt pathway may underlie the symptoms of AS.
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Affiliation(s)
- Li Zhang
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Peng Chen
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
- Neurosurgery Department, PLA 324 Hospital, Chongqing, China
| | - Lin Chen
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
| | - Tujun Weng
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Shichang Zhang
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Xia Zhou
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
| | - Bo Zhang
- Department 4, Daping Hospital & Research Institute of Surgery, Third Military Medical University, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing 400042, China
| | - Luchuan Liu
- Department of Stomatology, Daping Hospital & Research Institute of Surgery, Third Military Medical University, Chongqing 400042, China
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Teven CM, Farina EM, Rivas J, Reid RR. Fibroblast growth factor (FGF) signaling in development and skeletal diseases. Genes Dis 2014; 1:199-213. [PMID: 25679016 PMCID: PMC4323088 DOI: 10.1016/j.gendis.2014.09.005] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fibroblast growth factors (FGF) and their receptors serve many functions in both the developing and adult organism. Humans contain 18 FGF ligands and four FGF receptors (FGFR). FGF ligands are polypeptide growth factors that regulate several developmental processes including cellular proliferation, differentiation, and migration, morphogenesis, and patterning. FGF-FGFR signaling is also critical to the developing axial and craniofacial skeleton. In particular, the signaling cascade has been implicated in intramembranous ossification of cranial bones as well as cranial suture homeostasis. In the adult, FGFs and FGFRs are crucial for tissue repair. FGF signaling generally follows one of three transduction pathways: RAS/MAP kinase, PI3/AKT, or PLCγ. Each pathway likely regulates specific cellular behaviors. Inappropriate expression of FGF and improper activation of FGFRs are associated with various pathologic conditions, unregulated cell growth, and tumorigenesis. Additionally, aberrant signaling has been implicated in many skeletal abnormalities including achondroplasia and craniosynostosis. The biology and mechanisms of the FGF family have been the subject of significant research over the past 30 years. Recently, work has focused on the therapeutic targeting and potential of FGF ligands and their associated receptors. The majority of FGF-related therapy is aimed at age-related disorders. Increased understanding of FGF signaling and biology may reveal additional therapeutic roles, both in utero and postnatally. This review discusses the role of FGF signaling in general physiologic and pathologic embryogenesis and further explores it within the context of skeletal development.
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Affiliation(s)
- Chad M Teven
- The Laboratory of Craniofacial Biology, Section of Plastic & Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, 5841 South Maryland Avenue, MC 6035, Chicago, IL 60637, USA
| | - Evan M Farina
- The University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA
| | - Jane Rivas
- The University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA
| | - Russell R Reid
- The Laboratory of Craniofacial Biology, Section of Plastic & Reconstructive Surgery, Department of Surgery, The University of Chicago Medical Center, 5841 South Maryland Avenue, MC 6035, Chicago, IL 60637, USA
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Adams A, McBratney-Owen B, Newby B, Bowen ME, Olsen BR, Warman ML. Presphenoidal synchondrosis fusion in DBA/2J mice. Mamm Genome 2012. [PMID: 23179633 PMCID: PMC3560942 DOI: 10.1007/s00335-012-9437-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cranial base growth plates are important centers of longitudinal growth in the skull and are responsible for the proper anterior placement of the face and the stimulation of normal cranial vault development. We report that the presphenoidal synchondrosis (PSS), a midline growth plate of the cranial base, closes in the DBA/2J mouse strain but not in other common inbred strains. We investigated the genetics of PSS closure in DBA/2J mice by evaluating F1, F1 backcross, and/or F1 intercross offspring from matings with C57BL/6J and DBA/1J mice, whose PSS remain open. We observed that PSS closure is genetically determined, but not inherited as a simple Mendelian trait. Employing a genome-wide SNP array, we identified a region on chromosome 11 in the C57BL/6J strain that affected the frequency of PSS closure in F1 backcross and F1 intercross offspring. The equivalent region in the DBA/1J strain did not affect PSS closure in F1 intercross offspring. We conclude that PSS closure in the DBA/2J strain is complex and modified by different loci when outcrossed with C57BL/6J and DBA/1J mice.
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Affiliation(s)
- Allysa Adams
- Orthopaedic Research Laboratories, Boston Children's Hospital, Boston, MA, USA
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Vandenberg LN, Adams DS, Levin M. Normalized shape and location of perturbed craniofacial structures in the Xenopus tadpole reveal an innate ability to achieve correct morphology. Dev Dyn 2012; 241:863-78. [PMID: 22411736 DOI: 10.1002/dvdy.23770] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2012] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Embryonic development can often adjust its morphogenetic processes to counteract external perturbation. The existence of self-monitoring responses during pattern formation is of considerable importance to the biomedicine of birth defects, but has not been quantitatively addressed. To understand the computational capabilities of biological tissues in a molecularly tractable model system, we induced craniofacial defects in Xenopus embryos, then tracked tadpoles with craniofacial deformities and used geometric morphometric techniques to characterize changes in the shape and position of the craniofacial structures. RESULTS Canonical variate analysis revealed that the shapes and relative positions of perturbed jaws and branchial arches were corrected during the first few months of tadpole development. Analysis of the relative movements of the anterior-most structures indicates that misplaced structures move along the anterior-posterior and left-right axes in ways that are significantly different from their normal movements. CONCLUSIONS Our data suggest a model in which craniofacial structures use a measuring mechanism to assess and adjust their location relative to other local organs. Understanding the correction mechanisms at work in this system could lead to the better understanding of the adaptive decision-making capabilities of living tissues and suggest new approaches to correct birth defects in humans.
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Affiliation(s)
- Laura N Vandenberg
- Center for Regenerative and Developmental Biology, and Biology Department, Tufts University, Medford, MA 02155, USA
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Endothelium-targeted overexpression of constitutively active FGF receptor induces cardioprotection in mice myocardial infarction. J Mol Cell Cardiol 2009; 46:663-73. [PMID: 19358330 DOI: 10.1016/j.yjmcc.2009.01.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fibroblast growth factor receptor (FGFR) is expressed in a variety of cells and is involved in their proliferation/migration/survival. To elucidate FGFR-mediated specific action of vascular endothelial cells (ECs) on myocardial ischemia, we generated endothelium-targeted transgenic mice overexpressing constitutively active FGFR2 using Tie2 promoter (FGFR2-Tg). Infarct size, vessel formation and blood perfusion were significantly improved 28 days after myocardial infarction (MI) in FGFR2-Tg, compared with wild-type mice. Aortic ECs isolated from FGFR-Tg showed a marked increase in migratory capacity and tube formation. These in vitro angiogenic activities were blocked by PI3-kinase inhibitor. Whereas, parameters obtained from echocardiography were already improved at three days after MI. Cardiomyocyte apoptosis at the ischemic border zone was decreased in FGFR2-Tg (32.1%, p < 0.05) and cardiac mRNA expression of FGF2 (basic FGF) was also up-regulated (142%, p < 0.05) at 3 days after MI. 1% oxygen-mediated apoptosis was significantly inhibited in FGFR2-Tg-ECs and this inhibition was abolished by PI3-kinase inhibitor. FGFR2-Tg-ECs exposed to 1% oxygen exhibited enhanced phosphorylation of 416-Tyr-Src, 473-Ser-Akt, and HIF1alpha accumulation. The production of FGF2 was enhanced 2.1-fold in FGFR-Tg-ECs under 1% oxygen via the Src/Akt/HIF1alpha pathway, which induced the peri-vessel migration of vascular smooth muscle cells (VSMCs) and anti-apoptotic effects on VSMCs and cardiomyocytes. FGF receptor signaling in ECs promoted migration, survival and autocrine production of FGF2, leading to reduced infarct size, which is associated with anti-apoptotic action in the early stage and with enhanced angiogenesis in the late stage after MI.
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Harris SM, Ross AH. Detecting an undiagnosed case of nonsyndromic facial dysmorphism using geometric morphometrics. J Forensic Sci 2008; 53:1308-12. [PMID: 18798770 DOI: 10.1111/j.1556-4029.2008.00872.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Johns Hopkins University Center for Craniofacial Development and Disorders estimates that 1 in 3,000 children born in the United States is diagnosed with a rare form of craniosynostosis. Although the medical literature has documented numerous descriptions of craniofacial disorders from an anthropometric or genetic perspective, considerably fewer reports of these anomalies have been documented in the context of forensic anthropology. Similar genetic origins of many craniofacial anomalies generate ranges of phenotypic variation between and even within documented cases, producing difficulties in acquiring correct diagnoses. Identical physical characteristics manifested in different disorders create further complications in identifying a craniofacial syndrome in skeletal remains. Reported here is an unusual case of a possibly undiagnosed craniofacial abnormality in a set of identified skeletal remains from a North Carolina homicide case. Traditional metric and geometric morphometric approaches were utilized to further investigate morphological shape differences between the case study and a reference sample. Results show significant differences suggesting a nonsyndromic form of craniosynostosis.
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Affiliation(s)
- Sheena M Harris
- Department of Sociology and Anthropology, North Carolina State University, Campus Box 8107, Raleigh, NC 27695-8107, USA
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Eswarakumar VP, Özcan F, Lew ED, Bae JH, Tomé F, Booth CJ, Adams DJ, Lax I, Schlessinger J. Attenuation of signaling pathways stimulated by pathologically activated FGF-receptor 2 mutants prevents craniosynostosis. Proc Natl Acad Sci U S A 2006; 103:18603-8. [PMID: 17132737 PMCID: PMC1693709 DOI: 10.1073/pnas.0609157103] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Craniosynostosis, the fusion of one or more of the sutures of the skull vault before the brain completes its growth, is a common (1 in 2,500 births) craniofacial abnormality, approximately 20% of which occurrences are caused by gain-of-function mutations in FGF receptors (FGFRs). We describe a genetic and pharmacological approach for the treatment of a murine model system of Crouzon-like craniosynostosis induced by a dominant mutation in Fgfr2c. Using genetically modified mice, we demonstrate that premature fusion of sutures mediated by Crouzon-like activated Fgfr2c mutant is prevented by attenuation of signaling pathways by selective uncoupling between the docking protein Frs2alpha and activated Fgfr2c, resulting in normal skull development. We also demonstrate that attenuation of Fgfr signaling in a calvaria organ culture with an Fgfr inhibitor prevents premature fusion of sutures without adversely affecting calvaria development. These experiments show that attenuation of FGFR signaling by pharmacological intervention could be applied for the treatment of craniosynostosis or other severe bone disorders caused by mutations in FGFRs that currently have no treatment.
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Affiliation(s)
| | | | | | | | - F. Tomé
- *Department of Pharmacology and
| | - C. J. Booth
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520; and
| | - D. J. Adams
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT 06030
| | - I. Lax
- *Department of Pharmacology and
| | - J. Schlessinger
- *Department of Pharmacology and
- To whom correspondence should be addressed. E-mail:
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Abstract
Craniofacial malformations are involved in three fourths of all congenital birth defects in humans, affecting the development of head, face, or neck. Tremendous progress in the study of craniofacial development has been made that places this field at the forefront of biomedical research. A concerted effort among evolutionary and developmental biologists, human geneticists, and tissue engineers has revealed important information on the molecular mechanisms that are crucial for the patterning and formation of craniofacial structures. Here, we highlight recent advances in our understanding of evo-devo as it relates to craniofacial morphogenesis, fate determination of cranial neural crest cells, and specific signaling pathways in regulating tissue-tissue interactions during patterning of craniofacial apparatus and the morphogenesis of tooth, mandible, and palate. Together, these findings will be beneficial for the understanding, treatment, and prevention of human congenital malformations and establish the foundation for craniofacial tissue regeneration.
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Affiliation(s)
- Yang Chai
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, California 90033, USA.
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Rogers GF, Edwards PD, Robson CD, Mulliken JB. Concordant contralateral lambdoidal synostosis in dizygotic twins. J Craniofac Surg 2005; 16:435-9. [PMID: 15915110 DOI: 10.1097/01.scs.0000147385.76122.7c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Twin studies have been widely used to investigate genetic versus environmental causality of malformations. While there are numerous reports of concordant sutural fusions in syndromic twins, there are few cases in siblings with nonsyndromic single suture synostosis. Lambdoidal synostosis has no clear genetic etiology. Discordant synostosis has been reported in one monozygotic twin; there is also an unsubstantiated report of concordance in dizygotic twins. We describe dizygotic twins concordant for contralateral lambdoidal synostosis. Mutational analysis for FGFR 1,2,3 was negative. Given the low incidence, absence of reported inheritability, and lack of documented concordance in monozygotic twins, the pathogenesis of isolated lambdoidal fusion can only be ascribed to stochastic influences.
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Affiliation(s)
- Gary F Rogers
- Craniofacial Center, Division of Plastic Surgery and Department of Radiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Shum L, Nuckolls G. The life cycle of chondrocytes in the developing skeleton. ARTHRITIS RESEARCH 2002; 4:94-106. [PMID: 11879545 PMCID: PMC128921 DOI: 10.1186/ar396] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2001] [Revised: 09/14/2001] [Accepted: 09/19/2001] [Indexed: 11/21/2022]
Abstract
Cartilage serves multiple functions in the developing embryo and in postnatal life. Genetic mutations affecting cartilage development are relatively common and lead to skeletal malformations, dysfunction or increased susceptibility to disease or injury. Characterization of these mutations and investigation of the molecular pathways in which these genes function have contributed to an understanding of the mechanisms regulating skeletal patterning, chondrogenesis, endochondral ossification and joint formation. Extracellular growth and differentiation factors including bone morphogenetic proteins, fibroblast growth factors, parathyroid hormone-related peptide, extracellular matrix components, and members of the hedgehog and Wnt families provide important signals for the regulation of cell proliferation, differentiation and apoptosis. Transduction of these signals within the developing mesenchymal cells and chondrocytes results in changes in gene expression mediated by transcription factors including Smads, Msx2, Sox9, signal transducer and activator of transcription (STAT), and core-binding factor alpha 1. Further investigation of the interactions of these signaling pathways will contribute to an understanding of cartilage growth and development, and will allow for the development of strategies for the early detection, prevention and treatment of diseases and disorders affecting the skeleton.
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Affiliation(s)
- Lillian Shum
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Glen Nuckolls
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Abstract
Intramembranous bone growth is achieved through bone formation within a periosteum or by bone formation at sutures. Sutures are formed during embryonic development at the sites of approximation of the membranous bones of the craniofacial skeleton. They serve as the major sites of bone expansion during postnatal craniofacial growth. For sutures to function as intramembranous bone growth sites, they need to remain in an unossified state, yet allow new bone to be formed at the edges of the overlapping bone fronts. This process relies on the production of sufficient new bone cells to be recruited into the bone fronts, while ensuring that the cells within the suture remain undifferentiated. Unlike endochondral growth plates, which expand through chondrocyte hypertrophy, sutures do not have intrinsic growth potential. Rather, they produce new bone at the sutural edges of the bone fronts in response to external stimuli, such as signals arising from the expanding neurocranium. This process allows growth of the cranial vault to be coordinated with growth of the neurocranium. Too little or delayed bone growth will result in wide-open fontanels and suture agenesis, whereas too much or accelerated bone growth will result in osseous obliteration of the sutures or craniosynostosis. Craniosynostosis in humans, suture fusion in animals, and induced suture obliteration in vitro has been associated with mutations or alterations in expression of several transcription factors, growth factors, and their receptors. Much of the data concerning signaling within sutures has been garnered from research on cranial sutures; hence, only the cranial sutures will be discussed in detail in this review. This review synthesizes classic descriptions of suture growth and pathology with modern molecular analysis of genetics and cell function in normal and abnormal suture morphogenesis and growth in a unifying hypothesis. At the same time, the reader is reminded of the importance of the suture as an intramembranous bone growth site.
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Affiliation(s)
- L A Opperman
- Department of Biomedical Sciences, Baylor College of Dentistry, Texas A & M University System Health Sciences Center, Dallas, Texas 75266-0677, USA.
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